Unlikely since he counsels his viewers to believe in Our Lord, avoid things he (and, for that matter, others) believe to be associated with satanism such Quija boards, he speaks against premarital relations, he is pro-life, he sponsors nativity scenes for Christmas displays, his has started his own ministry, etc. The things King instructs people not to do are sins. The things King encourages people to do are either morally neutral or else are obviously positive things.
These are not the things you would expect an agent of the devil to do. Why would Satan want people to avoid sin??? And yet King encourages people to avoid things that are objectively sinful.
By their fruits, you shall know them. The things King encourages people to do will lead them to God or, failing that, at least won't lead them to the devil.
Careful.
You caught the part about me being Catholic, right?
Because I've studied a bit about satanism (only in summary) because I want to know who they are and what they believe. By and large, what King describes is who satanists truly are and what they truly believe. His descriptions of their methods of recruitment, infiltration and other things are absolutely spot on.
King has discussed possession, infestation and the like in some of his videos and interviews. I have studied a bit about demonology and if King's instructions are followed, the odds of having problems with infestations are pretty low. Again, what King says regarding demons lines up perfectly with what I've studied concerning demonology.
His fruits have deepend the faith of thousands of people and his instructions lead people (1) away from the devil and (2) toward Our Lord.
Again, I can understand if his testimony triggers severe cognitive dissonance for you because he's Catholic but everything he says lines up with satanism, demonology and Catholic doctrine. You can like that or you can dislike that but it's a bit presumptuous to casually dismiss King's testimony because muh bible or something.