Most Marriott owners can only reserve at 12 months out. Marriott owners that own multiple weeks can reserve at 13 months out. So you're still early, yet, to see any Marriott deposits.
If you are trying for a studio or 1 bedroom, your odds are good I think. Two bedrooms would be a little tougher. Maybe Dean will chime in later on the probability for October and various sized units at Koolina.
Take a look at these pictures:
http://travel.webshots.com/album/556022258QSTJYH