Honestly, this is one of the easiest fixes, since you probably do not need to do anything.
State law has required all new water heaters installed with bracing straps for at least 20 years. Since most water heaters in California are less than 20 years old, you can bet yours is already strapped down.
Flexible gas connectors are not required by law, but are recommended in the State building code. A reliable contractor or plumber can replace your rigid gas line with a flexible one.
Get that water heater secured for an earthquake!