I mean, if we want to go deep rabbit hole delving… S9 could be in the inter dimensional cleft.

Hear me out, as a grab my red string and tinfoil hat.

So, the expansions very loosely get inspiration from older FF games; FF3 and the Crystal tower/warriors of darkness for SB, A lot of FF4 obviously being in EW.

Assuming the trend continues, FF5 is the next reasonable source of inspiration. Major plot points include the inter dimensional rift between worlds.

In addition, FF5 had the Warriors of Dawn (whose trail we may or may not be following in 7.0), which included Galuf…(Krile’s father in both FF5 and 14). FF5 also involved the reunion of 2 worlds.

If I had to go even more deep, I’d say the game necessitates planar travel for future expacs as an alternative “solution” to merging worlds. Because we know at some point we are going to reunite Thancred and Y’shtola with their loved ones on the First.