Ooh, the promise of a Mac port is exciting, means I won't have to run the game via WINE anymore
(This was my workaround before I bought the Mac version of RPGMaker MV.)
If you have a known working Mac version of any other MV game, you can replace the assets in the app.nw folder (Mac) with the assets from the www folder (BS9).
Neat! I'll definitely keep that in mind for games that WINE doesn't want to run, for one reason or another.