Hi
If you are wanting to book a disney resturant then you do have to call and make a priority seating or a PS. You cannot book on-line.
UkAngel strongly recommends O'hanas and to be honest in all the trip reports I never heard a bad thing about it. So that where me and DH will be Christmas Evening.
Someone will be along shortly and give you the CRO telephone number. Sorry I don't have it on my new PC yet.