I would raise 4th given the dead nine. You might get rid of the bring in and take control of the hand with his checjing to you on 5th if he does not have trips. If you get rerasied, you need to fold there.

on fifth, the nines keep betting although the 7 seat is showing a scary board(although there are several hearts out). Given that he is still betting plus the potential hand of the 7 seat, plus your being sandwiched in, a fold is a good play. Tough to lay down those aces, but it seems appropiate here. You do not know if aces up or 3 aces would even be good enough if you caught them.