wheels and tires

hey everyone, I bought a 2017 trx 420 and the tires on it are garbage. I bought the machine brand new, and as of right now it has around 500 miles on it. The stock tires however look like they have 5000 miles on them. I can barely get out of the smallest mudhole unless it's in 4 wheel drive...

Factory rear tires were 22x10-9. I replaced the rear tires in 2000 with 25x9.50-9. I can not find a tire size of 25x9.50-9 I really liked the taller tires. Can anyone tell me if a larger wheel will work on this bike?