Avoid morning flights the day the cruise ends, especially out of LAX
LAX flights before 9 AM are not happening. Mid or Late morning flights can work if you wake up early.
Traffic in the LAX terminal area is usually horrendous (speaking as an LA local). Even if you don’t hit traffic going to LAX (that’s a big if), you could be stuck in the terminal area for 20 minutes, depending on which terminal your flight departs from.
An exception for flying out of Long Beach Airport (LGB), which is closer to the port and doesn’t have the terminal traffic issues of LAX.