Hey greedo you know a shitload more than me about poker but Im trying to learn. Id like to give it a go and try and figure out what hes got, so let me know how I do

Hands that beat you:
AA KK QQ - couldnt have played it this way surely. would have limp reraised preflop
JJ - maybe, but I would think he would raise UTG or raise less on the flop
A8, 98s, 87s, 8x, 77 - no need to shut you out with a huge bet, unless he got too excited or hes tryin to be a tricky bastard.

Hands you beat:
AK, AQ, AJ, Ax, bluff - just being a donk and trying to steal the pot, knowing you probbaly have two unpaired high cards?
66-22, 99, A7 or 7x - thinks youve got overs and he is winning?
9T,65 - open ended draw. could he really have called preflop though? maybe if it was sooted lol

Conclusion - he is a fish and has A7?
But since you posted it here he probably has 88....

I would call it easily purely because the big pairs would have limp rerarised you preflop, and if he had an 8 he would probably bet/raise the turn.