The window is 7:00am to 10:00am. They will assign color coded tags based on your deck. The problem is, what your color and time frame will be depends on a lot of factors. How many passengers request priority disembarkation. How many Mariner Society members there are and what ststus they have (# of sailings). The pax in suites get priority. Self assist (carry your own luggage) pax get priority.
If you know you want off early, you need an early flight booked and a copy of the itin to give the Purser's desk. Otherwise, plan to carry your own bags and hope a major percentage of the ship doesn't do the same.
Good luck, Neil