Re: How do you end the saga?
I personally don't think the story will end with IX. Disney didn't pay billions of dollars to make three movies and a smattering of spin-offs.
I don't think the sequel trilogy will end on a cliffhanger or anything, but I think it will definitely be a "passing of the torch" sort of deal where the new characters will work side by side with the OT guys, and then take the reigns for a fourth trilogy at some point down the road, with seeds having been planted for whatever comes next in the sequel trilogy.
At that point, it's way too far out for me to speculate on how the saga ends. And that's assuming that it ends with XII, which probably isn't a safe bet. They'll keep making these things as long they keep making money.
Your Game Music of the Week: "Ashura-Kai Authorized Shop" from Shin Megami Tensei IV