JJ overpair, bad river? line?

Or good river?
villian is a donk 41/24 w$sd is 30

Party Poker No-Limit Hold'em, $ BB (3 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

Button ($424.78)
Hero ($205.95)
BB ($225.68)

Preflop: Hero is SB with J, J. Hero posts a blind of $1.
Button calls $2, Hero (poster) raises to $8, BB calls $7, Button calls $7.

Flop: ($27) 3, 6, 9 (3 players)
Hero bets $20, BB calls $20, Button folds.

Turn: ($67) 5 (2 players)
Hero bets $40, BB calls $40.

River: ($147) 9 (2 players)
Hero checks, BB raises allin $143, Hero ...

Final Pot: $147

his agg freq on the river was like 20 but i really dont have many hands on him

Really though spot. This could be a bluff with the flushdraw obviously. A missed straight draw is not very likely considering the 5 filled the 78 draw on the turn.

Gah, really tough spot indeed. Have to think about an answer on this one.

Very hard for a massive bet to be "for value". If he had a hand worth having, he'd want to be called. Big bets on rivers tend to be big bluffs, in my limited experience.

This advice valid up to about 49.99NL

Really tough spot. I think I fold here, but its not an easy fold. What about a leading the river w/ a blocking bet of about 1/3 pot and fold to a raise?

bet the river, prob fold to a reraise. A 9 is a likely holding but once you check you give him licence to buy it unless you have a solid read he has shit.