I think I have a LAG image at this table although it's pretty doubtful this guy noticed it. Anyhow my stats are around 32/26/4 at this point with around 75 hands played at the table. I've been somewhat aggressive in pots against him though in the last 3-4 orbits and he is probably slightly annoyed, but I don't think it's got to the point where we can make a decision based solely on that.

Villain has 74/24/3.2 Stats over around 75 hands. I make the standard C-bet and get called OOP, and with the King on the turn I plan to check-fold.

On the river I make my set and I decide to overbet because I've already seen this guy call one with a top pair hand on a board where top pair was far from the nuts, and who knows what else he'll call with.

Unfortunately he shoves on me and I start crying.

Now what? Anyone finds a call? Or is this as obvious a fold as it looks like?

Merge $50.00 No Limit Hold'em - 4 players
The Official 2+2 Hand Converter Powered By DeucesCracked.com

CO: $41.09
BTN: $41.47
Hero (SB): $102.70
BB: $101.98

Pre Flop: ($0.75) Hero is SB with 9 9
2 folds, Hero raises to $2.25, BB calls $1.75

Flop: ($4.50) J 8 4 (2 players)
Hero bets $3.00, BB calls $3

Turn: ($10.50) K (2 players)
Hero checks, BB checks

River: ($10.50) 9 (2 players)
Hero bets $20.00, BB raises to $96.73, Hero...

He seems aggro enough to do this with Overpairs, slow played sets, and two pairs
So its a call

Board: Jh 8d 4s Kc 9d
Dead:

equity win tie pots won pots tied
Hand 0: 60.000% 60.00% 00.00% 33 0.00 { 9c9h }
Hand 1: 40.000% 40.00% 00.00% 22 0.00 { KK+, JJ, 88, 44, KJs, QTs, J9s-J8s, KJo, QTo, J9o-J8o }

how is this even close?
you double pot river, he shoved. this is QT like %99 of the time.

he very rarely has KK or AA here. The King is a pretty good card to barrel, so I don't really know why we're checking here.

Well then he doesn't have a pair here. Maybe he has 2 pair, but I'd guess QT a big portion of the time.

I have seen some fish make huge over shoves as bluffs when checked to, but without reads I'm folding his raise\shove all in.