Vs unknowns this is like dancing on the edge.

Given the pretty dry flop ur repping 79/T9/66/88 and maybe Jx, tho we´d probably raise a JT on flop. To pull a profitable move on river, we must know what´s his range, so we can figure out how his range will react to certain bets, and its not that easy to put ppl on a range when ur blindfolded. Definetly in his range are 99-TT and T9, depending on his postflop tendencies Axss and Jx and other stuff.

I´d go for $22 on river