Top advisers to Pope Francis said on Monday that the Vatican is preparing an official response to accusations that the pope helped cover up an American cardinal’s sexual misconduct. The statement from the “C-9,” the nine cardinals who advise Francis on Church matters, came on the first day of a three-day meeting with the pope, one of several throughout the year. The Holy See’s planned response will address accusations by Archbishop Carlo Maria Viganò — former Vatican ambassador to the United States — that Pope Francis covered up sexual abuse by now-disgraced former cardinal Theodore McCarrick. Viganò roiled the Church...