Since you asked, I do think it is odd that your grandchildren sleep with you if you have other accommodation available for them. Also, a nine-year-old should be able to bathe or shower alone. I would worry more about lack of independence at that age than anything improper, but at age 9 I would expect a boy to be more modest than you are describing.
Free printable topographic map of Morro Bay (aka Moro Bay and Bernard's Bay) in San Luis Obispo County, CA including photos, elevation & GPS coordinates.
A major landmark at this seaside community and ocean bay about 30 miles south of San Simeon is Morro Rock, a volcanic mound that rises 576 feet at the end of a narrow causeway connected to the mainland.