Only played 8 hands with villain at this point. He limped in 1 and raised 2 and nothing out of the ordinary to report.

MP: $28.20
CO: $52.85
Hero (BTN): $24.90
SB: $37.34
BB: $12.52
UTG: $25.15

Pre Flop: ($0.35) Hero is BTN with 9 9
1 fold, MP raises to $0.85, CO calls $0.85, Hero calls $0.85, SB calls $0.75, 1 fold

Flop: ($3.65) 9 7 7 (4 players)
SB checks, MP checks, CO bets $3.00, Hero calls $3, SB folds, MP folds

Turn: ($9.65) 8 (2 players)
CO bets $6.00

First I should probably take you through the reasoning for my flop play. I'm guessing a few of you are going to say something along the lines of "it's $25nl - don't slowplay just get the money in the middle'. However I just called the flop bet because it's a 4-way pot and I want people to come along. The FD and SD are both out there but I'm not scared about either - in fact I want them to hit. The only card's I'm worried about are overcards in case someone makes I higher FH but the chances of (i) an overcard hitting and (ii) someone making a higher FH are so slim that I'm prepared to take the risk.

So on to the turn - I'm disappointed no-one else came along. The way I see it is:
(i) The villain could be bluffing here because it's a scary board. If we raise he folds
(ii) The villain has trip 7s/flush/straight/overpair. We raise and we expect him to call every time.
(iii) The villain has a some kind of 2p/straight draw hand. We raise a small amount and expect him to call, probably fold to shove.

So what do we do here? Smooth call again hoping for him to donk into us again? Min-raise (donkish I know)? Or shove?

Call and let him shove river. If he checks river we shove. EZ game.

This. You'll have $14 behind in a $21 pot on the river.

Also flop is totally standard. Slowplaying 99 on this board is very different than slowplaying A7.