Chapter 9 discusses the importance of getting Sai Baba's permission to leave Shirdi. Does it also mention any consequences for not leaving after permission was granted?

Yes, Chapter 9 of the Sai Satcharitra addresses both sides of this rule. While it was crucial to get Sai Baba's permission before departing to avoid inviting obstacles and trouble, the text equally emphasizes that once that permission was given, a devotee should not stay in Shirdi for even a moment longer. The chapter explicitly states that staying longer after being told to leave also brings trouble upon one's head. This dual principle underscores the absolute importance of following Baba's instructions precisely for the devotee's own welfare, a lesson many experienced firsthand.