The teens have spoken: veteran ABC cop drama ‘The Rookie,’ which has emerged as a surprise hit with the under 18 crowd, has been renewed for a ninth season. With that, the Nathan Fillion starrer has become the third longest-running ABC drama series after ‘Grey’s Anatomy’ and ‘NYPD Blue.’ Deadline’s Editor-in-Chief, Nellie Andreeva, explains the mechanics behind its repeatability.