Cruising from San Francisco many times, I live here, I’ve never seen the arrival time in-forced or checked.
FYI…I choose to not want to deal with long check-in lines, if that happens, so I’m outside the terminal by 9:30 am & am usually one of the first group of people into the terminal, usually around 10 am after the ship is cleared. I then have a good place to sit down & am ready when the boarding is started.
Another plus is hopefully I can drop of any carryon & enjoy the ship & get ready for the MDR lunch at 12 noon.
Hopefully my bags might arrive sooner as they were checked in real early.
Staying at a hotel near the cruise terminal, Fisherman’s Wharf, will hopefully avoid any traffic problems getting to the ship.
Hope these tips are helpful.
Tom😀