Hi,
You can check this nursery out.
Gods Little Acre Nursery
19810 Almaden Rd, San Jose, CA 95120
I bought my Grafted cherimoya from Lowe's and sometimes I saw people bought from Home Depot too.
You also can learn more about the Tropical plants are growing in the SF bay area by join the FB group name "San Francisco Bay Area Tropical Fruit Growers"
Good Luck
Si Duong