I don't recall reading about too many people being completely shut out of Aulani for any times other than maybe Christmas / New Years. It seems that most people have been successful getting at least SOMETHING as long as they've been willing play around with their dates and / or unit views. Anybody who is unwilling to bend on one thing or the other may have a difficult time in a higher season like around the holidays or summer but I think October would be a pretty low season. Schools are in session and it's not the dead of winter when most people feel the urge to go somewhere warm. It's also not home to any major holidays, whale season or surf season so I'm sure you'll be fine as long as you're ready to go online as soon as your 7 mo. window opens. I'm guessing that October is actually probably one of the easier times to book there.