iRobot Roomba S9 Plus review

Could the iRobot Roomba S9 Plus be the future of robot vacuums?

iRobot Roomba S9+ close up
(Image: © TechRadar)

TechRadar Verdict

The Roomba S9+ sweeps away a host of bugbears that have plagued robot vacuums: emptying itself, capturing allergens, conquering corners and providing truly customisable vacuuming from an app on your phone. Its price tag might be steep but if you value spotlessly clean floors with minimal mess and effort on your part, the cost could be worth it.


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    Accurate room mapping system

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    Easy to operate

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    Efficient corner cleaning


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    Better on hard floors than carpet

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One-minute review

It’s been almost 20 years since the original Roomba robot vacuum launched and now robot vacuums are ten-a-penny, and a staple in many households.  

iRobot’s latest incarnation, the Roomba S9 Plus, might operate on similar principles, but thanks to a host of high-tech features, it’s a very different beast from the first iteration, and one of the best robot vacuums we've tested to date. 

Most noticeably, it’ll empty itself, meaning that rather than shaking out a dust box every few days, it’ll whisk out the contents from the vacuum into a bag in the charging station. As the capacity of the bag is 14.9oz / 440ml, which equates to around 30 cleans, this turns a daily job into a monthly one – great for those who are time-poor or dislike emptying the dust box. There’s also a filter for allergy sufferers that captures 99 percent of mould, pollen, and dust mite allergens.

Another feature that sets the Roomba S9 Plus apart is an advanced mapping system. Rather than being gimmicky, this has a practical purpose, meaning that the vacuum knows where it’s been, and where it still needs to clean, eliminating long running times that still end up with missed patches. It’s known as vSLAM navigation technology, where the robot gathers over 230,400 data points each second – resulting in a better clean and more control over which areas are vacuumed and when. While the mapping can initially seem like a chore, once it’s up and running, this provides cleaning flexibility and efficiency that budget models can’t replicate. 

A final advantage is that the Roomba S9 Plus is compatible with the iRobot’s Braava jet m6 robot mop. The two robots can ‘talk’ to each other, automatically vacuuming and then mopping without any additional commands, leaving hygienic floors behind – great for busy households, families, and properties with large areas to clean.

In addition, the Roomba S9 Plus promises a powerful cleaning system alongside its advanced features, which include a 3D sensor, wider brushes, and a corner brush. 

There’s no denying this is an expensive appliance but its cleaning ability, certainly on hard floors, means we think it really is worth it - making it ideal for those that want to outsource the vacuuming completely. With Roomba Black Friday deals abound, you might even find this at its lowest price yet.

iRobot Roomba S9 Plus price and availability

  • List price: $1,099.99 / £1,499.99 / AU$2,899

The iRobot Roomba S9 Plus, which is called the Roomba S9 Plus Robot Vacuum in Australia, is priced at $1,099.99 / £1,499.99 / AU$2,899. It’s available to buy now worldwide from the iRobot's website as well as Amazon.

It can be bundled with the Braava jet m6 Robot Mop for $1,349.99/ £1,999.99/ U$3,698. In the US, it also comes in a bundle with the Braava jet m6 Robot Mop and iRobot H1 Handheld Vacuum for $1,474.98. 

Compared to similar models, the iRobot Roomba S9 Plus is pricey but in return, it promises the brand’s deepest cleaning yet (up to 40 times the suction of previous generation Roomba vacuums), and a more accurate room mapping system so it won’t waste time going over the same areas.

Replacement dirt disposal bags cost $19.99 / £21.95 / AU$59 for three. 

iRobot Roomba S9+ upside down on a tiled floor

(Image credit: TechRadar)


  • Self-emptying bin 
  • 30% wider rubber brushes
  • Convenient control buttons on top

While the iRobot Roomba S9 Plus doesn’t look dissimilar to previous Roomba models – its rose-gold lid hiding the bin being one of the more noticeable differences – it’s host to many improvements. These include wider Dual Rubber Brushes (compared to the Roomba 600 series) and a brush with five angled arms to really get into corners and along walls. On top there are just three buttons – one to start and stop it cleaning, one for spot cleaning and one to send it home – all of which are useful if you don’t have your device to hand.

Compared to some, it’s a fairly weighty machine to carry from room to room at 8.15lb / 3.7kg, but not too large. Its height of 3.5 inches / 9cm isn’t too tall to tuck under most beds although it may be too tall to fit underneath some sofas. The Roomba S9+ is an average 12.25 inches / 31cm wide but it’s the charging station you may struggle to find room for. At 19 inches / 48cm tall and 12.2 inches / 31cm wide it takes up a decent amount of space against a wall, especially when allowing for the suggested clearance of 1.5ft / 50cm either side on top.

Set-up was fairly simple as it’s all done via the app (see below) but it can be frustrating waiting for it to map your home as a non-negotiable first task. There’s an extra filter and corner brush included in the box, plus a couple of dirt disposal bags. It might be a small thing but even the bags make sure you won’t ever have to come into contact with the dust from your floors – each one seals up as it’s removed from the charging station.

iRobot Roomba S9+ collecting dust from a red carpet

(Image credit: TechRadar)


  • Good dust pick-up on carpets and hard floors
  • Power Boost increases suction for carpets
  • Noisy when emptying

The iRobot Roomba S9 Plus sucked up all the fine dust, biscuit crumbs, and oats we sprinkled on hard floors but it did leave some fine dust behind on our medium-pile carpet, both on the Quiet clean setting and the more powerful Detailed clean. That said, even our usual vacuum cleaner struggled to pick up the fine flour afterwards, suggesting that it was fairly embedded in the pile after being rolled over a few times. 

Overall, we were impressed by the cleaning efficiency of the iRobot Roomba S9 Plus – while it can still get caught on rugs, it reached the edges of rooms to whisk away dust and navigated furniture well. The Power Boost feature automatically increased the suction when it detected carpets, too.

It is fairly noisy compared to other robot vacuums registering 61db on carpet and 64db on a hard floor on our decibel meter when using the Detailed Clean mode, which is equivalent to the sound of conversation in an office. While this level is acceptable, the automatic emptying averaged 77.5db - the same level of noise experienced when 25 ft away from a vehicle traveling at 65mph, so it might be best to keep the charging station out of a social area. 

Clean-up after vacuuming was effortless as the iRobot Roomba S9 Plus empties into the charging station, although the dust bag needs replacing after it’s been emptied into around 30 times (making for a monthly or bi-monthly empty). It’s actually the filter that needs more maintenance with a suggested weekly shake to clean (or twice a week if you have pets). It’s located within the robot’s dust box, so you will have to get a little messy to remove it, but it’s worth doing to maintain the filter’s anti-allergen properties.

iRobot Roomba S9+ on a tiled floor

(Image credit: TechRadar)


  • Connects via WiFi
  • Alexa and Google Assistant compatible
  • Find your Roomba feature

Connecting the iRobot Roomba S9 Plus to WiFi using the app was relatively straightforward although we had to move location a couple of times before it worked. The app itself isn’t complicated – there’s a history of previous cleans, the ability to save one as your favorite, details of the room map (with the ability to name each space and divide it as you see fit) plus a section for schedules. One thoughtful touch is that you can name your vacuum cleaner – handy if you have two on different floors. 

It took some time for us to work out how to change the suction level - an option that is stuck in the settings rather than being on the initial launch screen. Voice integration (available for Alexa and Google Home) is also not especially obvious – it’s hidden within a section labeled Smart Home. However, once linked, you can ask for it to start vacuuming, clean a specific room, or return to its dock.

One feature we did like is the ability to find your Roomba by tapping the app so the vacuum makes a noise. This came in handy when the robot vacuum became stuck under a bed. 

iRobot Roomba S9+ on a red carpet

(Image credit: TechRadar)

Battery life

  • Will ‘intelligently recharge’ for the amount of time needed to continue cleaning
  • Battery takes around three hours to fully recharge from flat
  • Indicator level doesn’t show a percentage

iRobot doesn’t make claims about how long the Roomba S9 Plus’s battery lasts between charges – perhaps this is because it’ll happily return to its charging station if it’s running low, and recharge just enough to finish the job. 

Our ground floor clean took just under an hour, and on the app, the battery level looked about half-full, although we’d have preferred if the indicator showed a percentage rather than us having to guess how much charge was left. It took three hours to fully recharge the S9+.

iRobot Roomba S9+ on a tiled floor

(Image credit: TechRadar)

Should I buy the iRobot Roomba S9 Plus?

Buy it if...

You have allergies
Thanks to the self-emptying function and a bag that only needs to be emptied occasionally, the iRobot Roomba S9 Plus is a good choice for those with pollen, dust mite, or mould spore allergies.

You want more control over your cleaning
If previous robot vacuums have missed areas or spent a long time cleaning, the iRobot Roomba S9 Plus makes an excellent upgrade. Being able to direct it to the room or area that needs attention is great for preserving battery life as well as unnecessary extra passes. 

You want to ask someone else to clean up
Being able to ask the iRobot Roomba S9 Plus via voice control to clean up spills when you have your hands full is a useful function – great for busy households or if you’re just dashing out of the door.

Don't buy it if..

You won’t use all its functionality
The iRobot Roomba S9 Plus has a lot of great features, but if you’re unlikely to use its app controls, a more simplistic model might be a better fit.

 You’re on a budget
There’s no getting away from the fact that the iRobot Roomba S9 Plus is a pricey machine. If you’re on a budget it's one to avoid.

You don’t want a noisy robot vacuum
During cleaning, we found the S9 Plus was louder than other robot vacuums we tested, and it reached peak noise level when emptying its dust box. If you’re not a fan of noisy appliances, then this isn’t the robot vacuum for you. 

First reviewed: July 2021

Rachel Ogden
Freelance Contributor

Freelance journalist Rachel Ogden has more than 20 years’ experience but for the last 14 years, she's worked exclusively in interiors, writing about everything from large and small kitchen appliances to the latest home tech. Partial to strong coffee, low-fat chips, and any kind of cake, there’s nothing she likes better than a time-saving gadget.