Would you recommend taking a train or a bus from the Hague to Delft?
Train, centre to entre and faster. It is only a short trip You can also take a tram, depending on where in the Hague you are starting. I am not even sure there are buses.
There is a train that connects the Hague and Delft which takes on 6 minutes. You can find schedules through the Deutsche Bahn. If you prefer the bus you can find info on that through Rome2Rio. Both the bus and the train take about the same amount of time so it doesn't really matter which one you take. I hope this helps some.
Many thanks for the helpful information, Abe and Chris.