Btn - $68.35
BB - $59.85 - Hero - Ac9h

Preflop:
Btn raises to $1.00, BB calls $0.50

Flop($2.15): Td9s2d
Hero checks, btn bets $1.62, Hero calls

Turn($5.24): Ah
Hero checks, btn checks

River($5.24): 7c
Hero bets $4.00

In actuality I bet $4.00. I wondering if I should bet bigger like $5.00 or even overbet to like $7.50? I'm trying to understand more about how my whole range looks in a certain spot and bet accordingly, more so than thinking, "My opponent probably has Tx, maybe JJ/QQ...how much would those hands call?"

I'm pretty sure my river betting range is pretty polarized here. I'm betting hands like QJ, missed flush draws like Kxdd, Qxdd, 65dd. Since I have a lot of bluffs and value hands like two pair/86/J8, I should have a large bet size. But when I bet $4.00, I wondering if its a leak to not be betting bigger?

P.S. Just thought about it, what hands should I be flop raising? QJdd, 87dd, 22, 99. What about QJo/Q8o?