I am arriving at DUS airport on March 16 at 6:55am. I need to catch a train to Amsterdam at 9:13am, same day. Which train do I take from DUS Flughafen to Dusseldorf HBF?
You don't need to transit through Düsseldorf HBF if you want to travel from Düsseldorf Airport to Amsterdam. From The Düsseldorf Airport, you can take a train to Duisburg and proceed from there to Amsterdam. Here is an example:
For schedules and fares, you can consult the website of the German Railways (available in many languages). You will see that there are plenty of trains between the airport and Duisburg HBF. So you can leave earlier from the airport in case you want to.
And if you still want to travel through Düsseldorf HBF, you can have a look at the following discussion: