flop super draw, river flush - thoughts?

I was a little lost on every street. Thoughts? and how much to bet the river? I feel as though fulltilt fr is making me lazy - nice for the bankroll though

Full Tilt Poker No-Limit Hold'em, $0.25 BB (8 handed)

UTG+1 ($1.95)
MP1 ($8.60)
Hero ($29.50)
CO ($15.60)
Button ($4.50)
SB ($9.95)
BB ($7.40)
UTG ($15.80)

Preflop: Hero is MP2 with [9d], [7d].
UTG calls $0.25, UTG+1 calls $0.25, 1 fold, Hero calls $0.25, 2 folds, SB completes, BB checks.

Flop: ($1.25) [5d], [Ks], [8d] (5 players)
SB checks, BB checks, UTG bets $0.5, UTG+1 raises to $1.7 (All-In), Hero calls $1.70, SB folds, BB folds, UTG calls $1.20.

Turn: ($6.35) [7h] (3 players, 1 all-in)
UTG checks, Hero bets $1.75, UTG calls $1.75.

River: ($9.85) [4d] (3 players, 1 all-in)
UTG checks, [color=#CC3333]Hero bets ?

I normally bet about 3.5 on river vs unknown here, he could have a flush but i think its more likely to be a weak made hand or a straight. If i think it will look fishy to villain that he will pay me off enough with a straight or even worse, i might shove.

EDIT : Rest of hand looks ok, i think i prefer a check behind on turn, but betting isn't horrible.

why did you make such an incredibly weak turn bet?

If you are going to bet there you need to bet more, $5 would have been nice.

Your bet is screaming for UTG to check/raise it and take the pot from you even if he has nothing.

As it stands i'd probably value bet about half pot and fold to a push on the river.