I never know how to play this hand and situations like the following come up quite often... Hand happened at 1/2.

Hero at ~$420, CO sitting on $400, SB has $250, BB covers.
Hero gets 99 in early pos, opens to 12. CO 3bets to 30, SB calls, BB calls.

CO who raised to $30 had 3bet several times already. He had to show on 2 occasions after 3 betting and had 99 and KK. SB had shown hands like 10-7s after calling preflop raises of $12, but BB seems to be playing pretty snug.

Pot - $120
Flop
8-6-3 (two hearts)
Hero????
I assume that SB or CO would 4bet with KK/AA but I could easily see them just calling pre with 1010/JJ/QQ/AK as neither of them had been active in 3bet pots previously.

I checked, CO (3better) checked, SB bets $50, BB calls, Hero????

Should I have led out? Should I be giving up when I miss my set?

Thanks

Check fold. At least one of them almost certainly has a bigger overpair or a set here

+1
Just maintain discipline in these spots, you'll be wrong on occasion but not enough for it tone +ev to do anything but set mine. HU is where it becomes tricky what do do with 99 on these boards and is much more player dependent.
Here is an easy fold though.

A snug BB is drawing or trapping here most of the time with so many to act by simply calling the $50. Fold and see what he shows if the hand plays out.

BTW, how come you checked & CO checked BEFORE the SB bet?!?

Thanks, just wanted to make sure that folding on this board isn't too weak esp given the SB's bet sizing.

What if everyone just calls my opening raise pre and I get the same flop. Am I leading out? Check/calling?

I lead those spots 100% of the time unless I catch someone giving something away. That's a clear bet fold situation.

Sry about that, monday morning haze. SB bet, BB called, i folded and cutoff folded. It went bet/call on turn and river and BB won with KK over JJ.

Meh in a 3 bet pot always versus snug players? These don't sound like guys who call or raise to 30 with AT or Q9s. Your 99 is basically the same as 77 or 98 here. Would you lead 77?

I had asked a follow up about what action to take if CO didnt 3bet and I simply had 3 callers. I believe he was responding to that.

True

pretty ez cf here

VS straightforward villains, donking small like 40 would serve you well.

The PFR will not bet air here 4 ways often, so we lose nothing by doing the donk bet. WE take control of the hand, we determine betsize and we cannot do much better than that.

leading out seems fine otf, but i think it gets tricky ott and otr.

I would personally find myself in some difficult situations if i lead out otf and one of the many bad turns came ie any heart or over card. this would be a grey area where you aren't quite sure if you are value betting thinly or turning your hand into a bluff, or you could even c/f the best hand depending on the action.

not saying leading out isn't the best option, just think it opens up many difficult situations later on in the hand. obviously, the more ABC your opponents are, the less of a problem it is to lead out otf.