Complex sentence: When she was nine, she auditioned at the Old Vic Theatre and in November 1915 she made her stage debut at the Old Vic in "Richard III" and appeared in many other Shakespeare plays.
Split into simpler sentences: When she was nine, she auditioned at the Old Vic Theatre. In November 1915 she made her stage début at the Old Vic in "Richard III", and she subsequently appeared in many other Shakespeare plays.