Calling the river is fine. It sucks but AQ is the best hand you could have in that spot after checking the flop. If you're not calling AQ, you're folding all of your hands.

Most players, especially in low stakes, are imbalance in their overbetting bluff-to-value ratio. With enough info, you could overfold or overcall against certain players including exploitatively folding everything in a capped range.

You don't have enough info and even if you did and he's never bluffing, maybe he's overbetting with A9 or A8? It could also be AQ. Obviously, overbetting isn't ideal for a hand like A9 but you never know what certain players are doing.

Calling this off I guess. Assuming this guy doesn't have enough worse value in his range (mostly due to sample size) would probably be a mistake. He clearly will have dominated value in his range after he check/raises. This is, however, getting towards the bottom of my calling range here. I think we can let go of our worse two pairs here.