A college tennis coach who also served as the personal instructor for former first lady Michelle Obama and her daughter, Malia, was among the 46 people charged by federal authorities in a sweeping college admissions bribery case announced Tuesday. According to the indictment unsealed Tuesday by federal prosecutors in Massachusetts, Gordon Ernst, the women’s tennis coach at the University of Rhode Island, is accused of conspiracy to commit racketeering during the years he served as a tennis coach at Georgetown University. There is no suggestion that Malia, a sophomore at Harvard, was implicated in the scandal in any way. Between...