On vehicles with a clutch having some sort of retaining spring, there should be NO movement at idle. That is the purpose of the spring. If there is movement at idle, then there is probably a malfunction of some sort. You could just set the brakes up to drag a bit at idle, and then you won't notice the problem. But you haven't solved it.
The reason there is a spring to hold the clutch back is to allow the engine to spool up and get some power behind it before it is trying to turn tires.