Capped Small Four Flush on the Flop

[why4duck]

Well, I'm holding the smallest possible flush, and UTG's action on the flop screams set or flush draw to me. It was obvious that two players were on big hands and everyone else was along for the ride. I don't see how I put UTG on A9 or a gut shot in this situation (or 2 pair -- 26, 69 or 29 UTG?). 78 is a possibility, but is it as likely as a set or a bigger (but not nut) flush draw? Since he was willing to 3 bet the flop I've got to discount the possiblity that he's holding 78 (unless it's 78c...which is not of the good). Perhaps I'm giving him more credit than he deserves, but with a 2 flush on the flop and all the ensuing action, I've gotta figure I have 6 outs if I'm open ended. With 8 or 9 outs I'll jam the flop with bets, not with 6 outs to make a hand vulnerable to redraws, though.

In any case, I don't think checking the river gives me a free showdown unless he's got a small flush (but necessarily bigger than mine) or has deuces full. If I bet out, sixes full or quad 9s and I'm definitely facing a raise to show down. If by some miracle he is holding 78, he can't call. So I'm not sure there's much that can go well if I bet out here.