CBS News’ “Gossip Girls” has been renewed for a ninth season.“Grimm” creator Joss Whedon will write and executive produce the series, which will premiere in 2019.The new season will air on CBS.The renewal comes on the heels of a ratings success that was bolstered by “Grizzly Peak,” “The Vampire Diaries,” and “Scandal.”“Grummy Girl” averaged 5.6 …