how many miles on the car? a toasted clutch before warranty period expires is a big red flag for most dealership warranty claims. under 'normal use' a WRX clutch should last 70,000-100,000 miles. It's a high-horsepower car with tons of grip, and launching on tarmac is really hard on the hardware.
maybe you don't think you're hard on the clutch, maybe you are, who knows. but if your tires are also toast before 36k, that's another big red flag. dealers are sensitive about owners of hot cars beating the crap out of the vehicles and then blaming "defective items' and wanting coverage when it's really not deserved.
you simply won't know for sure until they tear the thing down. trouble is, if it's at the dealership and they determine that it's NOT covered, what are you gonna do, say "put it back together and I'll go get it done someplace else for cheaper" ?? Heh, good luck with that.
on the other hand, you can just take the car to a good independent like Meyagi and pay up. you've had fun with the car....and you're about to discover that fun can be very expensive.