Seems odd that they haven't yet released it for their current OS, High Sierra but have released it for Windows though... i'm glad i found this thread though, thank OP!
Still no sign of iTunes 12.9 for 10.13 and earlier. Kind of a problem since my iTunes server is on 10.12 and I sync the library back and forth with my laptop (10.14). Hard to believe Apple's dropping iTunes support for anything other than Mojave...