Amigo --
You have a coating, you need to be washing it with CarPro Reset only, to keep it really clean and working at its best.. You are probably already doing this...
Having lived in California pretty much all my adult life minus a decade in the Pacific Northwest - and even there - I have had at least 6 different car covers on as many vehicles, and from decades of experiences with them, there is nothing better for protecting paint if its going to be outside all the time...
Car covers have evolved long ago from big thick cotton or cotton blend things to really light almost parachute type fabric that is easy to put on, take off, and store when not in use..
The good ones have great elastic that helps hold it on the vehicle tighter and can have a place on the sides of them where you can run a plastic covered cable through under the vehicle to the other side to lock in on the vehicle...
The good ones have great mirror pockets sewn in and some have a hole for external antennas to stick out of...
Yes, it would take a little time to install one on a Grand Cherokee - I know because I have an `09 GC too...
But it can be done and I am absolutely the SME to talk to about how to install it, take it off, wash it, and all the new words you will need to use when its windy..
What I can promise you, is that when you see your beautiful SRT8 every day, the cover will have all that gaga on it and the vehicle will be pristine underneath...
Let me know if you decide to go there, and I will help you further...
Good Luck !
Dan F