I guess the big question would be if they avoid Morocco altogether. That would take care of Agadir also. If they do that then the ship could do a similar itinerary that the world cruise is doing in reverse.

If they just skip Casablanca then there are really no other alernatives. I'm not certain of the distance, but maybe they could do a partial day in Gibralter, but that would probably still make it a partial sea day since I don't think they'd be able to make up the distance between Agadir and Gibralter that quickly to get a full day in Gibralter.