California Code, Vehicle Code - VEH § 12517

(b) A person may not operate a school pupil activity bus unless that person has in his or her immediate possession a valid driver's license for the appropriate class of vehicle to be driven endorsed for passenger transportation. When transporting one or more pupils at or below the 12th-grade level to or from public or private school activities, the person shall also have in his or her immediate possession a certificate issued by the department to permit the operation of school pupil activity buses.

(c) The applicant for a certificate to operate a schoolbus or school pupil activity bus shall meet the eligibility and training requirements specified for schoolbus and school pupil activity busdrivers in this code, the Education Code, and regulations adopted by the Department of the California Highway Patrol, and, in addition to the fee authorized in Section 2427, shall pay a fee of twenty-five dollars ($25) with the application for issuance of an original certificate, and a fee of twelve dollars ($12) for the renewal of that certificate.