Falls a little short
Well darn, the series had such a great run up 'till the very end.
First of all, I'll acknowledge this movie had the same awesome animation and production value as your movies always do, and that certainly gets my rating as high as it is.
HOWEVER, you seemed to have not had a good creative direction for this final episode. There's almost nothing original in it, it pretty much rehashes the jokes and concepts from the previous episodes (especially Jerry and the closet.) Also, for a "finale," I didn't expect to have another prequel. Or something that took place near the beginning of the plot.
But my biggest complaint is how "gloomy" it is. Like, the other Jerry episodes were sad, but were clever and funny at the same time. Here, there's only a few new jokes at all, the rest is just "here's Jerry's insanely horrible life" that you'd have to be a sadist to enjoy.
Although, my favorite part is the end. No, I don't mean the last 30 seconds, I mean the last 2 seconds right after the credits. I would have given this a 6, but that alone gave me some satisfaction and relief. So 7 starts it is.
Overall, you kind of slipped-up on this one (maybe that's why you ended it here, maybe you knew you were running out of ideas?) but it's still well animated, well voiced, and entertaining enough to watch.