Would the 12 give added stability so I could do this? Or would giving up the inflatable in favor of the revolution be required. (the posts seemed to indicate the revolution was less stable than the 12 inflatable)
IMO, The Revo is considerably less stable (without the Sidekick amas) than any of the inflatables. With the Revo's 28.5" beam vs inflatables 36" beam (with flatter bottom) I'm very surprised your dealer would think otherwise.
Yes, the i-12 has more stability by virtue of its extended length, but I wouldn't make the switch thinking it would solve your problems. Whereas the 12 is a great boat with an excellent payload, the 9 is lighter, more maneuverable and feels more lively, especially with a large rudder and Turbos. Additionally, it's amazingly versatile:
If you're otherwise happy with the the i-9, I think a little more practice in lighter conditions (trying the suggestions mentioned above) will make you more adept and comfortable with the idiosyncrasies of the boat.
This next pic illustrates ddrury's forward mast rake suggestion. This definitely improves the weather helm on the i-9. It also flattens the leach for better control in heavier winds.
I use a snap hook for quick connect and disconnect for the mainsheet and (tail) for the sail. the tail simply secures the sail when furled. If you find the permanently attached mainsheet hindering your furling efforts, this will make it easier.
You could use multiple knots on the tail for looser "expedient" furls.
Finally, you might try mounting the shrouds a little looser. This would allow the sail to dump wind easier for any gusts that come along.