A September Direct will surely be happening but I don't think they will announce any new AAA games.
The presentation will focus on Nintendo Switch Online and Switch Lite.
- SNES games for NSO
- A new free to play game for NSO
- Switch Lite showcase with Link's Awakening, Pokemon Sword/Shield and Luigi's Mansion 3.
- Some third-parties showcase: Doom Eternal and The Witcher 3.
I expect 2020 games to be announced in the January/February Direct, as usual.
There are several Nintendo games missing for tooo long that may be released next year:
- F-Zero
- Wave Race
- Advance Wars
- Wario Ware
- Kid Icarus
- Pikmin
If Nintendo announce just one of these I will be happy! :)