HU spot defending KT75 in BB to BTN. Villain opens pot, we call.

Hard to classify villain but think we'll just go with "not tough."

Flop J94r, we check, he checks back.
Turn J94 - 3, adding a FD to the board.

If we pot turn and villain calls, what are our best bluff cards OTR?

Ordinarily I'd say pairs are good because villain should be betting all sets, J9 OTF. And while some villains can be flatting any 2p with a 3 OTT, there shouldn't be too many of those.

However: I think AJ will check flop as well and and some 9xxx hands will call turn for a bet hoping to improve to 2p. So this makes me feel like pairs might not be as good as advertised because there's a good chance we run into Jxxx on a J river. And on a 3 or 4 river, I also think AJ will look us up a lot of the time.

As far as straights that miss us, villain shouldn't have strong wrap draws as he'd have bet them, though i could maybe see T8 checking back flop.

And flushes, I just am not sure if we should consider it a good bluff card or not, because that also should reasonably fall within villain's check-flop-but-call-turn range.

Thoughts? Thanks.