Number of possible ways to make a hand-
QQ: 3 ways
99: 3 ways
set -(6)

Q9: 9 ways
Q8: 3 ways
98: 3 ways
two pair - (15)

JT: 16 ways
straight - (16)

If he has a random hand and he bets the same way with all these hands then he is likely to not have the higher set. The straight is most likely. Two pair is next most likely. The higher set is least likely.