If you're a sole proprietor who comes to students' homes, you're going to pass every legal test of "physical presence in California".
Note that Lambda School's lawyer interpreted the law the same way you'd like to -- Lambda School doesn't have a physical presence in California because it doesn't operate any classrooms. But the state felt differently.
And the state is pretty unambiguously correct on this point -- Lambda School is apparently incorporated in California as Lambda Inc. with a business address of 921 Crescent Court, San Ramon, CA 94582.
( https://www.bloomberg.com/profile/company/1574959D:US )
Fascinatingly, they seem to have been incorporated in 1983.