No reads. I'm wondering if this is a bet/fold or check/fold.

PokerStars No-Limit Hold'em, $1.00 BB (6 handed) Converter Tool from (Format: Bet The Pot)

CO ($100)
Button ($103.60)
SB ($100)
Hero ($212.25)
UTG ($144.80)
MP ($164.75)

Preflop: Hero is BB with , . CO posts a blind of $1.50.
UTG calls $1, 1 fold, CO (poster) checks, Button calls $1, SB completes, Hero checks.

Flop: ($5.50) , , (5 players)
SB checks, Hero bets $4, UTG calls $4, CO folds, Button folds, SB folds.

Turn: ($13.50) (2 players)
Hero bets $9, UTG calls $9.

River: ($31.50) (2 players)
Hero ?

Does it change if I know this guy is a donk?

I think that this is C/F. Your image needs to be pretty bluffly here and he needs to be uber donk that either floats KQ or AT and will call a river bet. Otherwise you have practically bottom two so I don't think you get called 50%+ of time with 1 pair hand.