What is the primary rule for devotees visiting Shirdi regarding their departure, as explained in Chapter 9?

Chapter 9 of the Sai Satcharitra outlines a very strict and important rule for all pilgrims visiting Shirdi: one must not leave without Sai Baba's explicit permission, and conversely, one should not stay for even a moment longer once that permission has been granted. The text clearly states that departing without Baba's consent is an invitation for obstacles and trouble. The chapter mentions that many devotees experienced this firsthand. This principle underscores the importance of complete adherence to the Guru's guidance for a safe and blessed pilgrimage, as acting outside of his orders could lead to significant suffering on the way back home.