The program wants students who express the intention to serve the inland SoCal community. If you receive one of their scholarships, then there is an explicit commitment to remain in the area for 2.5 years for the 2-year scholarships, or 5 years for the 4-year scholarships, otherwise the scholarships convert to loans that must be repaid. If you don’t receive funding, then there’s no enforceable obligation.
And re: BYU, yes, you need a full year of high school VPA credit, which is the equivalent of a single semester of a college course. BYU high school classes are measured in high school semesters, so you’d need two.