I just returned from NCL Spirit Alaska sailing round trip from Seattle Our cruise departed from Pier 66 and arrived at Pier 91 (due to other NCL ship arriving same day).
Pier 66 had a strongly worded banner in the check-in area about not bringing any marijuana (THC and CBD) including a long list of different formats (edibles, vape, etc.) but I didn't notice any additional screening to detect such products (like dogs). Just the usual metal detector and quick x-ray of your bag. (Not sure if there was additional screening of checked baggage).
Granted our cruise sailed from one weed legal state to another with two stops in a weed legal country... including a stop in Vancouver where a lot more is legal (mushrooms, LSD, etc.).
I didn't see any additional screening at ports of call either, just very light ship security.
So if you can't smell it or smoke it you could probably bring something at embarkation or pick it up along the way. Of course there's always the chance of a random screening, but I don't think it's a regular practice. Like if TSA screened for THC and CBD at airports it would slow things down so much planes would leave empty....