post-flop hand from the blinds

[Dallara]

PP 20+2, Level:3 Blinds(25/50)

Seat 9 is the button
Total number of players : 6
Seat 3: ( $1045 )
Seat 4: ( $430 )
Seat 8: ( $2835 )
Seat 9: ( $1440 )
Seat 10: Villain( $1535 )
Seat 1: Hero ( $715 )

Trny:15589500 Level:3
Blinds(25/50)
** Dealing down cards **
Dealt to Hero [ Jc Qc ]
4 folds, Villain (SB) raises [75].
Hero calls [50].
** Dealing Flop ** [ 4d, Ts, 9s ]
Villain checks.
Hero checks.
** Dealing Turn ** [ Tc ]
Villain bets [50].
Hero calls [50].
** Dealing River ** [ 2c ]
Villain bets [50].
Hero?

OK, areas for comment:
1) I call defending my blinds, I think this is standard although I might fold here if I have less chips.
2) He checks a pretty harmless flop. I find this a little strange and decide to take the free card with the OESD. Should I bet here? I suck at betting draws.
3) Weak turn bet and I just call. Others raise here?
4) Weak river bet but I have nothing. Fold or call?