2 limpers
hero hj 9s 9h raise
btn 3bet
bb c limpers c hero c
flop Ad 9d 5d
checked to hero bets
btn c one limper
turn 6d checked to hero ??

The pot contains 9 Big Bets. On the flop we had 5 players. So what are the chances that noone held a diamond. Well were are out(2 cards off the deck) and now we know that 4 diamonds are on the board. That leaves 49 cards with 9 Diamonds left. At the flop we had 4 players and 8 unknown cards. This gives this probability that noone has a Diamond without thinking about their action on the flop.: 40/49 * 39/48 * 38/47 * 37/46 * 36/45 * 35/44 * 34/43 * 33/42 = 17%.
Do their action indicate a flushdraw? Yes. So let us lower the value even more of our hand. We are the one drawing most likely so I would play this like a chicken and c/c. I would even crycall a riverbet unless the action goes crazy.

I'd probably 4 bet preflop. As played I'm check calling the turn.

I bet and see who acts behind me, if raised I at least call ( do we have any relevant reads here?. We are most often ahead and we have 10 outs to a full house or better, lets not lose our nerve. Winning big pots is better than winning small pots.

Are we, Bona?

With the fourth down and 2 villains, there's a 60% chance we're facing the made flush if we give them ATC -- higher than that if we assume that the folders held no flush cards. I don't think its a value-bet, nor can we force a mistake.

c/c the turn, IMO. And, presumably, call any raises -- fearing AA or 87 is MUBS.

BUT -- I've been out of the game (and the Forum) for 6 years. Totally expecting to be wrong!

I misread the action. I was thinking we were after the flop with 3 diamonds showing. Based on the actual hand I agree with c/c turn and see what the river brings.

I'd bet again on the turn.

reads and stakes could change that.