Allegedly their phylacteries are the result of them misinterpreting God's command to bind His law to their heads (which just meant *remember the law*, not literally binding copies of the Law to their heads). But it could just be cover some occult practice like you say, since I do not trust their official explanations of anything. I wouldn't be to surprised if instead of copies of the Law, those phylacteries had some occult curses in them).
Virtually all ancient polytheism IDs the 5 visible planets as top gods among the pantheon.