I think that may have been a federal court, and Gray Davis refused to appeal.
Perhaps the California Supreme Court did shoot down a law denying public school to illegal aliens; however, the United States Supreme Court decided the matter in Plyler v. Doe (1982). Strictly speaking, that decision struck down Tyler Independent School District (Texas) rule charging $1,000 tuition to each illegal alien. Gray Davis then served as first-term state assemblyman in California and obviously did not appeal because he lacked standing as a non-party to the case. Moreover, one cannot appeal a Supreme Court decision to any entity other than the Supreme Court itself, which naturally rarely entertains such appeals.