Alright so I gave you this problem, and now I'm going to work it out for you based on your assumptions and check what you've got here as far as the combinations go. I might make a mistake but let's hope I don't.

Pre-flop Range: 99+,ATs+,KJs+,QJs,AJo+,KJo+,QJo

I'll make a suggestion here that you combine the hands that include both suited and offsuit versions when listing ranges to make things more concise and easier to work with. For example:

New Pre-flop Range: 99+, AJ+, ATs, KJ+, QJ

We hold AK. I didn't say whether it was suited or offsuit, but it won't matter a lot for this example. If you want to organize the counting of these combinations, then a quick way to do it is just list out how many combinations there are of each hand in each grouping. For example:

99+ = 99(6), TT(6), JJ(6), QQ(6), KK(3), AA(3) = 30 combos
AJ+ = AJ(12), AQ(12), AK(9) = 33 combos
ATs = 3 combos
KJ+ = KJ(12), KQ(12) = 24 combos
QJ = 16 combos

This gives us a total of 106 before the flop. The flop comes Qs9h5c, so here's the new range breakdown:

99+ = 99(3), TT(6), JJ(6), QQ(3), KK(3), AA(3) = 24 combos
AJ+ = AJ(12), AQ(9), AK(9) = 30 combos
ATs = 3 combos
KJ+ = KJ(12), KQ(9) = 21 combos
QJ = 12 combos

For a total of 90 combos after the flop. You think he's folding everything but QQ+, 99, AQ, KQ, QJ. The combinations for his continuing range are:

AA(3), KK(3), QQ(3), 99(3), AQ(9), KQ(9), QJ(12) = 42 combinations

Based on this assumption, he's continuing with 42/90 so he's folding 48/90 = 53.33 percent.