Incredibly odd thought, but maybe Ep 9 could use a CGI Recreation of Sebastian Shaw as Anakin’s force ghost, who has been trying to contact Kylo Ren but has been consistently pushed away by Snoke. Who better to tear down Vader idolization than Vader?

Or to be perfectly honest, Hayden Christensen is only 8 years younger than Anakin when he died…

Rey and Kylo could essentially train together under the force-ghost training of Luke, Obi-Wan (Ewan McGregor aged), and Anakin(Hayden aged). Even offers the opportunity for a cameo of Yoda and Qui-Gon watching the training from afar.
Then Rey and Ben go off to defeat his former allies, the Knights of Ren.
Ultimately the film ends with them/Finn/Rose/Chewie/Poe bringing down the First Order and ending with a “What’s going to control the Galaxy now?” “The same thing that’s always controlled it. The Force.”
“Then what do we do?”
“Maintain the balance”…