I can't speak to how religious he is personally. I only know that:
- He defends religious freedom vigorously.
- He recognizes that his talent is "on loan," just as Christians recognize that they are only "renting" their personal possessions.
- He has always talked about what interests him, and has never been bashful about saying so. The mere possession of a corporate jet and intense like for playing golf don't make him a rampant materialist.
- He annually donates program time and writes a huge check to the Leukemia Society, which raises millions in the space of three hours (I can't name another host that does anything similar).
You don't know that he isn't focused on eternal goals. He keeps religious arguments out of his broadcasts because he thinks it's no fun to hear Christians bash each other over Biblical interpretations (and I agree).