I will first start this off by saying that I actually own a 98' Grand Prix GTP, not a Bonneville :(. The reason I post on here is because of clubgp.com'* LONG approval process and it also seems like the intelligence is a higher over here.

Anyway to the point. I have recently found out that the unlovely sound at idle is from my supercharger, as confirmed by removing the belt and starting the engine. The only time I hear the sound is at idle, as when I slightly press the gas it goes away. I've obviously trolled enough websites to determine that it is more than likely the Coupler since the pulley has about 1/8" play.

My question is, in the meantime waiting for the pulley to arrive, is it fine to drive the car normally with the supercharger belt removed?

You can drive it since the SC belt doesn't drive anything else. How bad is the sound that you don't want to drive it with the belt on?

You will not find yourself stranded. My sister is driving without the belt on her 99 SSEi right now while she gets through the holiday hard times to get money for new belt and idler pulley.
So, yeah, go ahead and remove the belt and *try* enjoy some SC-less drive time. Won't hurt anything.

Generally, a rattling coupler can be driven with a belt for quite some time. Leave the belt on and don't beat on it, and you'll be fine.