My two girls were 9 and 11 when they first went on their Dis Cruise (4 years ago), the first year I tried really hard to get them to join the kids club, making them both try it just once to see how they felt.
I thought that would be where they would get most benefit out of the cruise, but I was wrong they never went back to the clubs.
The next three cruises they said they just wanted to be with us, do the bingo, the shows, we played boardgames etc, second dinner sittings, everything was together as a family and they think the cruises were the best ever.
I am sure your kids will enjoy it, if you let them find their own level.