More than 40 years after its theatrical release, “The Exorcist” remains one of the most memorable and recognized horror films of all time. Adapting a film of that stature into a television show comes with its fair share of risks, but Jeremy Slater, executive producer of FOX’s new show “The Exorcist” (series premiere this Friday, Sept. 23, at 9 p.m. ET/PT on FOX), is not so easily scared.