Yes, there is 1 bolt on the rear side of the shield
* If it is hanging down then you lost the bolt or it pulled through the thin metal of the shield. Get a new bolt if needed, and use a washer so that the bolt doesn't pull through the metal. Also you can use metal hose clamps to wrap the entire cat shield which seems to be most dealers method of dealing with these shields. Heat shield problems and the SVTF are very common.
Yeah, there is a bracket that is bolted to the back of the motor where the cat angles up and turns to the rear of the car to meet the flex. I've heard of those beaking for some but me, I've ran an ORP or highflow longer than the stock cat so I never had an issue with the bracket. It's something that you can inspect when you are under the car if you get the chance.
i just put and orp on that fixed it. But if you want to leave it on you could get new bolt as mentioned above and get a big hose clamp or two and that would stop the rattling, also help holding it on. i clamped mine before i put the orp on it worked great.