Villain was solid but not great. I put him on the flush draw and trusted my read. Who plays this the same way and do you call on the river? If so, what sized bet would you call?

Party Poker No-Limit Hold'em, $0.5 BB (9 handed)

SB ($49.5)
Hero ($53.1)
UTG ($47.5)
UTG+1 ($46.35)
MP1 ($49)
MP2 ($60.35)
MP3 ($63.4)
CO ($50.85)
Button ($49.75)

Preflop: Hero is BB with , .
2 folds, MP1 calls $0.50, MP2 calls $0.50, MP3 calls $0.50, CO calls $0.50, Button calls $0.50, SB completes, Hero checks.

Flop: ($3.50) , , (7 players)
SB checks, Hero bets $3, MP1 folds, MP2 folds, MP3 folds, CO folds, Button calls $3, SB folds.

Turn: ($9.50) (2 players)
Hero bets $6, Button calls $6.

River: ($21.50) (2 players)
Hero checks, Button checks.

Final Pot: $21.50

Results in white below:
Hero has 8c 3s (two pair, kings and eights).
Button has 9s 7s (two pair, kings and sevens).
Outcome: Hero wins $21.50.

I would normally assume at the turn he has the K/TJ or the spade draw, against most of my opponents I would value bet the river and maybe fold to a serious raise. You are ahead here at least 70% of the time against most of his possible holdings that don't raise the turn.

If I did check the river would break it apart by player types. Semi-solid I call up to half pot. Once it gets into the yahoo range I might call full pot. In the blufftastic range I check raise all in If I checked I would be obligated to call a bet of some sort from almost any one, however, if I bet I can fold to a big reraise against most opponents.

Edit:
If you check one of the reasons you must call a bet is because it looks like you have busted spades, and a far weaker hand that an aggressive player may hold will bet. Betting really sorts out what is going on, while checking makes it harder to play if they opt to bet.

ReEdit:
I didn't even notice the king just that it was a club, I should stop posting past the first 40oz.

I wouldnt have even bet the turn. Theres a very good chance he has a king and youre dead in the water.

I figured him for the K or flush draw. If he had a king, he was aggressive enough to raise me so I would find out my place right there. Since he just called, I put him squarely on the flush draw so no reason to bet the river. He might bet as a bluff. I was pretty much calling almost anything on that river and the turn had me convinced I was right. Sound too reckless on the river?