$100NL - Thoughts on Gaybetting river

Villain is running 18/14 which is very tight for 5max. From UTG, he is opening only 10%.

What are your thoughts on betting super small like this on the river when you are fairly confident that the best hand villain can have here is A high(or maybe 44, 66)?

$0.50/$1 No Limit Holdem
5 Players
Hand Conversion Powered by weaktight.com

Stacks:
UTG ($100)
CO ($97)
Hero ($171.20)
SB ($148.95)
BB ($151.85)

Pre-Flop: ($1.50, 5 players) Hero is BTN :9h: :9d:
UTG raises to $3.50, 1 fold, Hero calls $3.50, 2 folds

Flop: :5s: :3d: :5h: ($8.50, 2 players)
UTG bets $6.50, Hero calls $6.50

Turn: :3h: ($21.50, 2 players)
UTG checks, Hero checks

River: :7d: ($21.50, 2 players)
UTG checks, Hero bets $4

nb

im pretty sure 1010 + fires here for villain so a bet of this size is kinda cool. you can get looked up by worse pairs and the ever-popular ace high.

I think a $9 bet might get called at the same frequency. Or at least more than half as often, so make it potentially better than $4.