saw flop|saw showdown

Hero ($109.50)
UTG ($33.15)
MP ($97.40)
Button ($90.00)
SB ($65.20)

Preflop: Hero is BB with , . SB posts a blind of $0.50.
1 fold, MP calls $1, Button calls $1, SB (poster) completes, Hero checks.

Flop: ($4) , , (4 players)
SB checks, Hero checks, MP checks, Button checks.

Turn: ($4) (4 players)
SB checks, Hero bets $3, MP calls $3, Button folds, SB folds.

River: ($10) (2 players)
Hero checks, MP bets $9.5, Hero??

just wondering what you guys think.
is pushing too agressive here? and only get called by better FH

at that time i push as i thought the only hand that he could have that beats me is A9 and 99 since AA and AQ probably raise PF, and i really thought he would call me with Ax.
at the moment iam trying to reduce my SD (it is around 42bb/100), and i think not pushing on hand like that my be the way.
in this hand he had , and i lost