I did a little bit of digging through Disney's financials I've found the numbers and some clues to what's going on. Sorry if this includes a lot of numbers.
The 89% occupancy rate is for Fiscal Year 2015 Quarter 1 (FY15Q1). This is compared to 81% occupancy FY14Q1 and 81% for FY13Q1. Disney's Fiscal year runs Approximately October - September (Technically the Fiscal year/Quarter ends on the last Saturday of the month). So these results are for basically Oct-Dec. This is for Domestic "Theme park and Resorts". So would include WDW,
Disneyland, and the hotel portion of Aulani. Without more time, I can't tell if it include occupancy on the cruise ships or not. Their results are in the segment. The other piece of information to throw into the mix is the number of rooms available to rent. This is varies slightly from year to year based on how many DVC members trade out but changed significantly because of the Poly Longhouses getting converted to DVC on the negative side and Aulani Hotel (non DVC) rooms getting completed on the positive side. So looking at just Q1 results (in thousands of room nights).
FY15Q1: 89% occupancy * 2,591 room nights = 2,306 room nights rented
FY14Q1: 81% occupancy * 2,620 room nights = 2,122 room nights rented
FY13Q1: 81% occupancy * 2,623 room nights = 2,125 room nights rented
So, the 89% occupancy rate is a huge increase but that is partly because the cut room nights available because of the Poly DVC conversion. Had the conversion not been going on it would still be an impressive 88%. It's still almost 200,000 more room nights rented. Also, this is just 1 quarters results. FY13's occupancy rate for the whole year was 79% and FY14's Occupancy rate was 83%.
Disney had a stellar Halloween/Thanksgiving/Christmas season this year in terms of onsite hotel stays domestically. If you look back Historically, Disney likes running in the upper 80's to lower 90's in terms of occupancy rates. The lower numbers for FY13 and FY14 could be because of Art of Animation and filling up because of it.