Yes you are fine with cutting the plug off. You will be perfectly fine just wire nutting the wires together. Those plugs are just for guys like me, say I have to come to that fixture in an office building and change the ballast. That plug is there so I can turn power off of just that one fixture without having to turn all the lights in the office off. There are 4 holes on one side of the plug so that power can come in AND out. They do this so the electrician can just send short whips from one fixture to another. Just cut it off and wire nut the white and black wires to your cord. It'll work just fine that way.
We don't inherit this world from our parents, we borrow it from our children.