[Buzz]

L0QTiS - You don't know if you're up against a set of nines or a full house (nines over deuces). CO probably a set of nines, as you suspect, but could have flopped a full house, in which case you're already dead.

I think you can assume that if CO does have a full house, and if you check, CO will bet behind you. If CO doesn't (yet) have a full house and you check, CO might bet behind you or might take the free card.
If CO does bet behind your check on the third betting round, and if you call the raise on the second betting round, then I think you call the bet on the third betting round (because CO might not yet have a full house).
If CO takes the free card, then I think you assume CO doesn't yet have the full house and in that case, I think you can afford to bet on the river, and CO should probably call you.
If CO bets behind your check on the third betting round, then I think you check and call on the fourth betting round. But if CO doesn't have a full house, and doesn't make one on the turn or river, but bets the turn, it will be pretty hard for you to bet into CO on the fourth betting round.
Therefore, what you win if you have a winner and two low cards don't come, is 18 small bets. If low does come and you win, you maybe only win 7.5 or 8.5 small bets, or so, depending.

(Phew). Babble, babble, babble. Kind of garbled reasoning above. I don't even want to re-read it myself. Seemed right while I was wading through it. Basically you're screwed because you're out of position.

Low figures to get there 240/990 and not get there 750/990.
Figure your win as 18*750/990+8*250/990, on average, or about 16SB, on average.
meanwhile, your loss will probably be 5SB. So you're going to get about 3.2 to 1 pot odds.
Meanwhile, if CO doesn't yet have the boat and if CO has 3 live cards, the odds against CO making a boat, considering your own cards, are
only about 465 to 355 or about 1.3 to 1.
Thus it looks like CO has a better chance of making a boat than you're getting for projected pot odds.
If that wasn't bad enough, one of those other opponents very well could have the other nine and also be drawing for a boat.
And then there's still the possibility that CO already has the full house.
When you put it all together, it really does look rather bleak.
I might have some wrong figuring in there because CO might have a nine and an ace and/or jack, which would cut into his odds a bit. But even so... it still looks very bleak.

I don't see how a re-raise would help you here. You're either going to get bumped again or not, and either way, I think you're backing off on the third betting round.

You're simply out of position here.

Goes against the grain to fold a flopped full house, even an under-boat. You don't want to look weak/tight, a terrible table image, and you could be getting bluffed or semi-bluffed out of the pot, especially if you already have such an image. Well... actually if you do fold here, it will probably look as though you were bluffing yourself and therefore won't hurt your table image.

All things (hopefully) considered, I agree with Stevo and think folding to the raise is probably your best move here.

Just my opinion.

Buzz