Before I pop brain cells on this, take a look at this thread!! I know it's the Commander forum, but it applies to the Maverick... and all your vehicles for that matter. To make it a short story... put the octane rating in your gas tanks that the manufacture recommends!! Anything more you're wasting your money and will actually lose horsepower, anything less can destroy an engine. Anyway...here's the thread. Fuel ?? - Can-Am Commander Forum
I believe Can am recommends 91 for their engine which probably has to do with the 12:1 compression. I wouldn't go any less or any more than that. I think the Mav has a knock sensor so you could probably get away with 87, but you may cause engine damage with prolonged use.
The Maverick’s engine is designed to optimally run on 91-octane fuel, but it does include a knock control sensor that will allow it to run on 87-octane fuel without damaging the engine (91 is optimal, of course). This all leads to 15% more horsepower than the Polaris RZR 900 XP and 30% more than the Arctic Cat Wildcat. Can-Am also claims best-in-class power-to-weight ratio that is 5% better than the RZR and 31% better than the Wildcat.