15mm hub is a decent upgrade, the wheel will track better, especially if you’re riding ‘hard’ trails and hitting jumps.
At that price Rockshox is your best bet, a Reba with 120mm would be a good choice. Merlin Cycles usually have some good deals:
http://www.merlincycles.com/rockshox-sid-rl-forks-2013-59427.html
SIDs are a very nice XC fork.
If you’re looking at 9mm, your best bet is going to be used, I’d pop up a WTD ad in the wanted section of the classifieds.
Be warned though, buying used forks is a minefield – as you have no idea what the forks are like inside and below the seals – they could have been ridden dry, and have worn bushes, and be buggered – but they’d look fine on the outside.