Help settle a debate: this guy's bluff good or bad?

[FoxwoodsFiend]

10/20 NL. I've been aggressive preflop but not out of line and haven't been caught doing crazy [censored] yet, but definitely reraising more than most.

Anyway, villain raises to 70 on the CO, I make it 250 w/xx from SB, he calls with TT.

Flop(510): 5 [img]/images/graemlins/spade.gif[/img] 6 [img]/images/graemlins/spade.gif[/img] 7 [img]/images/graemlins/diamond.gif[/img]
I bet 300, he calls
Turn (1110): J [img]/images/graemlins/club.gif[/img]
I check, he checks.
River (1110): 9 [img]/images/graemlins/heart.gif[/img]
I bet 760, he insta jams for 900 more. Anyone like this push by him?

Also, if you're in my shoes and there are no real reads either way what's your minimum hand to bet this river with?