I won some chips earlier when someone pushed w/Q6 and I called from the BB w/JJ. Other than that I haven't shown down any hands. The CO is very loose and aggressive. I've seen him limp and call raises with junk hands like 82s and open from EP w/A3.

PokerStars No-Limit Hold'em Tourney, Big Blind is t30 (7 handed) Poker-Stars Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

SB (t2350)
BB (t2720)
UTG (t1320)
MP1 (t725)
Hero (t2190)
CO (t1760)
Button (t2435)

Preflop: Hero is MP2 with A, A.
2 folds, Hero raises to t90, CO calls t90, 1 fold, SB calls t75, 1 fold.

Flop: (t300) 5, 9, 9 (3 players)
SB checks, Hero bets t200, CO raises to t900, SB folds, Hero...?

I don't see how I can fold here. The CO's range is too large and you can't really lay down hands this big with under the mere suspicion that you're beat.

Shove. Judging by your reads, he probably has some weak flush draw or maybe some kind of 5. If he has 9 5, let's just say he won't make very much money in the long run.

Yup, the quality of play is terrible in these $1.20's. He could have a naked flush draw, a 5, or TT-KK. If he has a 9, so be it. But you're way ahead of the range he could be playing and you have to push big hands hard in these donkfests. If he turns over 98o, that's just the way it goes.

lol, i've folded about 2 flopped overpairs in $1 SNGs and both times it was the wrong move.

I agree with Breslin, shove and hope for the best.