50NL 99 on 66K Flop, fold, call, raise?

[1outer]

I've been playing mostly solid for the past 30-40 hands and have only showed down good hands, getting respect from table. This is villain's first hand, therefore have absolutely no read from him at all.

Full Tilt Poker Game #2383479072: Table Dartford (6 max) - $0.25/$0.50 - No Limit Hold'em - 23:38:17 ET - 2007/05/08
Seat 1: Green Diamonds ($50)
Seat 2: pavelzzz ($64.35)
Seat 3: Daniam ($38.65)
Seat 4: mcgrooge12 ($64.05)
Seat 6: markcards ($69.90)
mcgrooge12 posts the small blind of $0.25
markcards posts the big blind of $0.50
The button is in seat #3

Holecards:
Dealt to mcgrooge12 [ 9d,9c ]
Green Diamonds raises to $1.75
pavelzzz folds
Daniam folds
COLONELCUSTER sits down
COLONELCUSTER stands up
mcgrooge12 calls $1.50
markcards calls $1.25

Flop:
[ 6d,6s,ks ]
mcgrooge12 checks
markcards checks
Green Diamonds bets $4.50
mcgrooge12 calls $4.50
markcards folds

Turn:
[ 6d,6s,Ks ] [ 5d ]
mcgrooge12 checks
Green Diamonds bets $11.50

As I have no read on him, i decided to play him as if he were a sane person. These games are generally pretty loose, so I do not neccesarrily think he HAS TO put me on a good hand. He could put me on any ace, suited connector, pocket pair, my range is just as large as his.

[TheRenaissance]

Preflop: I like to 3b w 99 in position. Here you are oop so your plan should be to see a flop and continue if you like the texture/flop a set.
Flop: Not a good flop for you and you should check fold, especially as you dont close the action, and you are oop. Heads up/in position I guess a call is ok, here it is spew.
Turn: Very easy fold against an uknown.