I've been bagging fish for people for 10 years, an hour and a half should be no prob, assuming things are done correctly, like a properly sized bag, not too crowded, 1/3 water with 2/3 air, etc. If they have oxygen, they could last many times that. Remember, fish that are imported are in the bags for 24-48 hours. Couple tips...
-Keep em dark, like in a cooler. Makes the fish's metabolism slow down and reduces stress and breathing.
-Don't ask to see them eat. I know everyone says you should, and it's good advice in theory, but stressed fish will throw up in the bag, which can quickly kill.