When there's a cruise calling the Rotterdam port, there's usually a line of taxis available. If all taken, walk in 1 minute to NH Hotel, where there's also a taxi stand. If that's also taken, walk 4min to the metro station Wilhelminaplein, which is the fastest way to Rotterdam Central station (around 7min). Tickets can be bought at the machines or online: https://tickets.ret.nl/#/tickets/2uur
Train tickets can be bought in advance and downloaded on app/phone or print-out. "Intercity Direct" is the fastest train to Amsterdam Schiphol airport, 25min, 0 stops, runs around 3x per hour: https://www.ns.nl/en/journeyplanner/#/?vertrek=Rotterdam Centraal&vertrektype=treinstation&aankomst=Schiphol Airport&aankomsttype=treinstation&type=vertrek&tijd=2023-06-11T10%3A54&firstMileModality=PUBLIC_TRANSPORT&lastMileModality=PUBLIC_TRANSPORT
Do check the https://www.ns.nl/en site on day of travel to see if there are any delays/strikes etc.
Hope this helps!