[Caroian]

Don't worry, booking in Japan doesn't seem to be done anywhere near as far in advance as we are often used to. If you want to stay in a Disney hotel, these aren't available to book until 5 months before your stay on a room only basis, or 6 months in advance if you book a "vacation package" (but these don't appear to be good value). Buying your park tickets when you arrive is also very much the "done thing". There are several non-Disney hotels in the Disney area, and the Hilton Tokyo Bay is the one that often comes up as having flash sales, but again it is highly unlikely that you've missed these yet.

Hotels elsewhere in Tokyo and Japan don't seem to book up far in advance, and often aren't available to book at all until months - rather than years - in advance. For September next year I'd say that now is a good time to start to your planning and if you find things unavailable to book it is more likely that they aren't available yet, rather than that they are booked up.