2-5nl

Preflop:
Folded to MP raises to 15. CO calls 15. Hero with 64calls 15/600.

Flop (50): 444

Checked around.

Turn (50): J

Checked around.

River (50): 9

MP leads for 55/300. CO calls 55/1200. Hero?

raises to 130

Fold pf.

Bet the turn. If they don't call, there was no money to be made in this hand.

As played on the river, shove. Zeebo Theorem says nobody can fold a FH. They'll call if they have anything.

+1 someone has a 9 believing your are bluffing them off a chop

There is nothing wrong with playing hands like this from the button, you will fold them most of the time, but when they do hit, they pay nicely. I will, however, note that post-flop skills should be better than average.

I don't think a turn bet is mandatory. In this spot, if I bet the turn at all, it would be a weak bet, like $10, or $15. The best case would be to get raised and then led into on the river.

This is part of where post-flop skills come in. If you think either player is sticky, then yea shove - it's a judgment call. Otherwise, a raise to $155 for value. It also matters which player you think is more sticky. If it's the MP, then raise to $300 (MP's stack) and hope the CO comes along.

In short, what you do depends on the current dynamic. There is no simple answer.

I was kinda liking a jam, but MP would probably have bet an overpair on flop and certainly turn, so may just have two high cards. CO just called river, I think a J raises, so at best he likely has a 9. Not convinced anyone is calling a Jam with A9.

Jam ... who cares what they have, there's no way you have a 4.

A small raise will look like exactly what it is--bait. I would shove and see if anyone is suspicious enough to call. I think that a big raise is more likely to be called than a small one in this situation.

Results.