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:
If Nintendo announce just one of these I will be happy! :)
They've made a ton of Fire Emblem games as of late, so I wouldn't be surprised if they took a break and focused more on Advanced Wars. I certainly love both series. Kid Icarus Uprising was absolutely amazing and the best Star Fox game since Star Fox 64 (yeah you read that right). I would love a sequel to those as well as Pikmin.