You really couldn't go into the "wheels that fit 2011+ widebody WRX's" thread and read a little bit? All your questions are answered a million times. You being new has nothing to do with anything, it means you should search instead of posting new theads. You even said these questions have been asked 100 times, why would you ask them again?
I'd go 265's. Might as well maximize the tire you can fit. Why get 9.5" wheels if you don't get wide tires? I've run 275's on a 9.5" wheel on a Mustang.
And rolling your rears is all you need.
Try tire rack, discount tire direct, or tread depot.