And no I dunno why there is a ? in the title.

Full Tilt No-Limit Hold'em, $0.05 BB (6 handed) - Full-Tilt Converter Tool from FlopTurnRiver.com

Hero (Button) ($8.02)
SB ($5.38)
BB ($8.49)
UTG ($9.42)
MP ($7.25)
CO ($5.11)

Preflop: Hero is Button with 6, 6
UTG bets $0.20, 2 folds, Hero calls $0.20, SB raises to $0.55, 1 fold, UTG calls $0.35, Hero calls $0.35

Flop: ($1.70) 9, 8, 7 (3 players)
SB checks, UTG checks, Hero checks

Turn: ($1.70) 6 (3 players)
SB checks, UTG checks, Hero bets $0.90, SB calls $0.90, UTG calls $0.90

River: ($4.40) A (3 players)
SB checks, UTG checks, Hero checks

Total pot: $4.40 | Rake: $0.29

Is betting the river here just going for too much thin value vs. your standard 5-10nl donks?
I'm for sure betting again if just one of them calls, but is it just too likely that one of them has something like 55 or some random 5 or 10 that they're playing stupid?

Yeah I wouldn't bet there.

You're instabetting if it's HU to the river and get checked too right? Are we b/cing if so, or B/fing?

Sure you can get a random Ax of diamonds to call a small bet. But hoping to get 2 streets of value here and not running into a straight is pretty unlikely.

Bet/call would be pretty bad. I think betting it heads up is thin too. It's different betting this board than like a 679T board or something like that, where they need to have an 8 or a two card straight. That board has two one card straight possibilities. The amount you're giving up by never betting in this spot is probably very close to 0 especially considering if you're betting this board how many times you'll value own yourself with weak 2nd pair and strong third pair etc.

I play these stakes too and what I've observed is that players tend to be pretty passive overall. When you get called by two on that turn, and then they both check the river, there is a solid chance one of them has a 5 and is afraid of the higher straight.

Like I think if you're looking to plug leaks or w/e that this spot isn't it. The key to thinnnnn value bets is having good notes/reads on your opponent and betting because of that. We really don't have great definition of villain's hands here, other than they checked river and most people don't check the nuts on the river.

I think heads up on the river you can bet/fold but with two players there is no way this is a bet

i think you get check raised too much by flushes and or AA decent pot just don't risk it i know everyone loves the value bet but play it safe