Islamic schools are the primary reason that I have opposed education vouchers in my state. We do not have any that I am aware of, but once the government starts paying for things, we tend to get lots of those things. Reference: Unwed mothers, Dependent children, etc., etc.
It’s simple, classify Islam as a political ideology not a religion and then investigate them the same way you would a neo-Nazi organization. At the same time restrict Islamic immigration and you won’t have a problem.