I note younger travelers have not responded to you. We traveled with our granddaughters to Alaska but they were 12 and 10 so we were not offered any communication devices (on Disney we had pagers when they were younger). But I think Princess now offers pagers for parents on their cruises. But I don't know what the age situation is. You should call Princess and ask about the childrens program. 10 year olds and especially 12 year olds really do not want to have to contact the parents!
Enjoy your cruise, your children certainly will.