Id definitley check that turn but when he checks again on the river id probably make a value bet

edit: i didnt see that this was NL.. I would check here in this situation

no, I would not expect him to be betting and calling like that with a 9 in his hand

...so he could easily have two pair or a set and is also afraid of the str8

i don't see any reason not to bet the turn. if you get CR, you can throw the hand away. betting the turn does a few things, esp since you have position:

1) it probably lets you see a free showdown. if you check the turn and villian bets the river, you're going to be tempted to call what looks like a possible bluff. by betting the turn, you probably get to check the river, plus you give yourself a chance to pick up the pot. more importantly, you have better information about the hand at a pretty low risk.

2) i think you're value betting here better than half the time, which is all you need in this spot, really. my thought is that you're up against a) an overpair smaller than yours b) A7 or A8 c) two overcards. look at the flop play. does the opponent really have the low end of the draw with the 4? it's a very loose call if he does. chances are he doesn't have top pair and open ended because a lot of players will come back over with that in a HU situation, especially against such a strong bet. it's unlikely he already has the straight because, again, you showed such strength that he would've probably re-raised thinking you could not get away.

i'm really thinking he has A7, but that's just a guess i suppose.

maxpot

Yea, I unhappily check behind. Don't know much about NL ring though.