Since the CIF championships are cancelled all schools are in summertime rules right now according to CIF's press release in early April. This means the HS kids can run for a club, summer style training, etc. Not to mention all seniors in 12th grade right now are done with their CIF eligibility since the season got cancelled. They are not under any CIF rules that stop them for doing a time trail , an unattached race. or having their own private coach. (SOUTHERN SECTION UPDATE – 4/8/2020). They technically can be coached by who and when they want.
The only thing stoping them would be if this was their registered CIF dead period. Since most southern sections school are still in session I would guess Mira Costa and Newbury Park are still in school.