When I go to the Disney web site and filter for cruises "8 to 13 nights" and "April + May 2022", I get:
Please Chart a Different Course
We don't mean to take the wind out of your sails, but there are no available cruises that match your request. Explore other selections for Leaving, Sailing to, Departing from or More Filters and we'll help find the cruise that's right for you.
Don't know what that "means" for existing reservations, but it looks like new bookings aren't being allowed, at least for now.