My itunes movie won't download? - 1

Last night, I tried to download a movie onto my iphone via itunes. I paid for it and I have enough space on my phone to download the movie, but it has been stuck in the downloads section of itunes all night and it just says "waiting". How can i download the movie and get rid of this?

Is it necessary to have OS X 10.8 for apple apps development? How to upgrade from 10.7.5 to 10.8?

I'm going to create iphone mobile app and i have mac os 10.7.5, but i came to know that it is compulsory to have os 10.8 or later for app development. My questions are:

1) can i create app with 10.7.5 by installing old version of x-code?

2) if no, if i upgrade my mac to os x 10.8, will it create any problems to the applications which are installed already and should i need to take complete backup of my system before upgrade?

3) can i upgrade to os x 10.9 mavericks (because it is free of cost) and develop the apps?