Bad coil wouldn't make a noise of any kind. Though the bike would only run on 4 cylinders, each of the 3 coils fires 2 cylinders. I would take a guess from the noise you describe, either a started drive or possibly an alternator bearing. Would need more info to make a better guess, does it get louder when you pull in the clutch lever? Sometimes the push pin gets dry and make funny noise when the clutch is pulled in. Noise comes from the area of the slave cylinder under the fuel petcock.

The key is in the description
I have a 2000 standard 13 years old.. question how long of life does the ignition coil last?... today I went to start it and it missed no turn over and I hit the starter switch and it started sluggishly. when I got home I started it again to see and I heard a whiny spinny sound if that makes sence when I started it. .... the bike ran fine after I started it.. never stalled at a stop..... im thinking my battery maybe 4 years old...
I interpret the whinny noise as the starter didn't fully engage and just whirled freely. Something that'll happen on a bad /low battery,faulty switch, or connections.

given the discription, IMHO