Morning or afternoon birthday party?

Would you rather do a 4 year old birthday party from 9:30 - 11:30am or 3:30 - 5:30pm? It would be on a Sunday at an indoor playground. I think the afternoon would be nice to not have to stress about getting out the door in the morning, but the venue will probably be less crowded in the morning. Also kids probably in a better mood. Give me your thoughts!

Edit: We can only book a time slot at 9:30 or 3:30, otherwise I agree a later morning time like 10/10:30 would be ideal. The comments do seem to be divided depending on if your family are morning people or not so I guess it's impossible to try to please everyone!