Plot Bunny Theater: My Take on Season 9 · 4:54pm Jan 22nd, 2020
Basically at the end of season 8 Cozy Glow doesn't try to trap the Main 6 in Tartarus. Rather, she traps them in a time spell that sends them all to different timelines/universes.The same timelines we saw in Cutie Remark and a few we didn't see.
The season ends with her ascending to Alicorn and laying claim to the throne.
She also scattered Discord into six parts with the same spell across these timelines.