It's a common set up provided you use spacers.
Just run a google image search for "JK stock wheels 35" and you'll get many, many photos.
9" wheels are pretty rare. 8" are more common and are used for 35s by the majority of folks running 35s on aftermarket wheels on this forum.
Of course, thats actually counter to what the tire manufacturers recommend, which is a 9" wheel. But the main issue they're concerned about with using a narrower wheel is even tread wear. 12.5" tires will wear more in the middle 10" or so rather than all the way across unless you go with a 9" or wider wheel.
But for jeepers, there are benefits to consider going to a narrower wheel. Namely, it functions as a "poor man's beadlock" by gripping the wheel more tightly when you air down on the trail.