My DH always gets his Visa approved in about 1 hour and he goes to America 3 times a year. 9 wks in plenty of time to get organised. How many days are you going to give yourself in LA? Most flights get into LA early morning there, so your best bet is to try staying awake all day and sleeping when it is night there. Has worked for me and DH whenever we have gone. Doing it at the end of the trip means something for your DD to really look forward to but will you get lots of when are we going to Disneyland?