I completely agree with the poster above.
We took the train, it is 3 Euro/person, and then you can take Tram #5, takes another 5 or so minutes from Zuid train station. We actually just walked from Zuid Station to Hilton, it took us about 15 minutes, we only had carry-on luggage, so that was easy.
A taxi from Hilton to the airport was 28 Euro and you can charge it to the hotel as well, so that is an option, and same price as a shuttle (if you have 2+ people), so you may consider that as well.
Best,
PedroNY