I agree that calling down to the river is probably the way to go, but I don’t think I’d be very likely to consider defending T7o versus a 3x open. I think fold pre is better.

On the river, with villain’s sizing so small it’s likely to be fairly exploitable for you to consider folding the Ts, but since there are a ton of combos in villain’s range that include the Js/Qs/As and it seems like this river sizing is significantly less likely to be a bluff, we can consider making an exploitative fold there. So many of villain’s 2-barrelling combos are going to include one of those three cards, and I can’t see villain turning a weak showdown value hand like T9dd into a bluff too often, so we kinda need villain to be bluffing this sizing with something like QJdd or another 2-barrel bluff hand in order to be confident. We also have a ton of Js and Qs hands in our call-down range (all JsTx and QsTx combos, Qs8x, perhaps some Js9x) and some As combos (AsTx, As8x, As2x) that we can be check-raising the river with, so we don’t have to be too concerned with protecting our range.

That said, I suppose there’s a small chance villain has something like K9o with the 9s and is value-betting, so that’s one in the ‘call’ column. I doubt calling is bad but we might be able to make a big fold if we think villain’s sizing is very rarely a bluff.