C/R'd on river by LAG

Villain is 42/11/3.8 No reads.
PokerRoom No-Limit Hold'em, $0.5 BB (5 handed) converter (http://www.selachian.com/tools/bisonconverter/hhconverter.cgi)

<font color="#C00000">Hero ($54.90)</font>
Button ($45.25)
SB ($25.05)
<font color="#C00000">BB ($42.45)</font>
UTG ($194.45)

Preflop: Hero is MP with K/images/graemlins/heart.gif, 7/images/graemlins/heart.gif.
UTG calls $0.50, Hero calls $0.50, <font color="#666666">1 fold</font>, SB completes, BB checks.

Flop: ($2.50) 7/images/graemlins/spade.gif, 3/images/graemlins/heart.gif, 2/images/graemlins/heart.gif <font color="#0000FF">(4 players)</font>
SB checks, BB checks, UTG checks, <font color="#CC3333">Hero bets $2</font>, SB folds, BB calls $2, UTG folds.

Turn: ($6.50) 9/images/graemlins/diamond.gif <font color="#0000FF">(2 players)</font>
<font color="#CC3333">BB bets $2</font>, Hero calls $2.

River: ($10.50) 9/images/graemlins/heart.gif <font color="#0000FF">(2 players)</font>
BB checks, <font color="#CC3333">Hero bets $4.5</font>, <font color="#CC3333">BB raises to $19</font>, Hero?

I put him on hearts, 9's full, or trips. Since he made the flop call, x9 seems less likely than the others. The river C/R is very bad if he doesn't have the full house. I'm getting 34/14.5 = 2.3:1

Is this a fold or a crying call?
Do you check behind on the river?
Any other comments appreciated as well.

[xorbie]

fold and keep the stack.

Id probably call. He doesnt know you have a flush.

Surely he would raise the turn with a draw heavy board if that 9 made him two pair.
Also surely hes not stupid enough to give away a free heart if he flopped trips.
Id be more worried about a suited ace as it looks like hes drawing.

I think you where beat by an ace high flush here, but a lot of times your seeing a 9 here, a worse flush or someone make a move when a super scare card like that drops.
I like betting my nut flush draws because of how often people bluff me when i hit it.

I think you have to call or push with a k high flush probably has trip 9's or smaller flush. Fold to those bets and they will keep coming.