We have been on the Radiance in may this year to the Hawaiian Islands. And I´m sure, that the RadianceClass Ships are accessable for handicapt people. We saw many people in normal wheelchairs, as well as in their scooters.
On each deck are handicapt cabins, we have been in one of them on the sister ship, Jewel. It has enough space in the cabin, a huge bathroom and the closet is also accessable.
If you have to tender, people from the crew help to get into the tenderboat and off the tenderboat. So absolutely no problem.
BTW, welcome the cruise-chat