On 10/1/2021, the governor of California announced that the state will eventually make COVID-19 vaccination mandatory for students to attend school in-person.
The requirement will go into effect upon full FDA approval of the COVID-19 vaccine for age groups within the K-12 grade span. Based on current information, the state expects the requirement to apply to students within the 7-12 grade span on 7/1/2022.
The governor directed the requirement to carried out through the California Department of Public Health, which will follow the procedures established by the state’s legislature to add the COVID-19 vaccine to other vaccines required to attend school in-person.
https://www.gov.ca.gov/2021/10/01/california-becomes-first-state-in-nation-to-announce-covid-19-vaccine-requirements-for-schools/ - text of the governor’s press release.