make sure you apply before sept 30 or you'll pay more. Once you lodge your application you can rearrange and change your preferences as many times as you like.
yes up to nine, you can apply for one tonight for example then log on tomorrow and completely change your preferences. I already know i'm going to change mine probably alot as I change my mind alot. anyway goodluck.
Don't worry you can change them as much as you want until like 2 weeks before they're released. After that though, you're locked in unless you want to wait for another round.