Yes, you can make ADR's without being on the DDP, or without staying on site and even if you're just going for the day.
Credit Card guarantees are required for a few places, CRT & Norway's Princess meals. You may cancel those up to 48hrs in advance without being charged a cancellation fee.
Dinner shows (Luau, Hoop Dee Doo Review) are different and require payment at the time of reservation.