What is required to be certified without taking the Instructor Development Course? Who has to approve that certification? Is there a procedure outline to do this?

Chapter 8 of AUXMAN states:

B.2.d. Waiver Requirements
In some cases, the Director may waive requirements for IT. The Director may delegate this duty to the DSO-MT. The decision to waive requirements will be based on sufficient documentation, but at a minimum, the waiver will include the following criteria:
 (1) Submit documentation of two or more years of recent work experience as an instructor such as a certified schoolteacher or as a full time or adjunct instructor in the military, business, academic or professional communities. The number of years‘ service and recent experience will weigh in the Director‘s decisions. The FC will review and approve the application before forwarding to the Director.

 (2) USPS members, who have completed the USPS Instructor Qualification course and are graduates of the Coast Guard‘s Instructor Development Course (IDC), will be certified as ITs upon application.