Possible Kingdom Hearts appearances in upcoming events

2.8 date will be at tgs o dont know about the playstaion meeting

I would not expect anything from the Playstation meeting.  This isn't going to be an E3 or PSX type of conference: this meeting is going to be almost all about new PS tech (Slim, Neo, possible new handheld, and PSVR) with few game announcements (most likely showing existing games running better on Neo and some launch announcements for the handheld).  At most Square would only be present to show something developed for the handheld and/or to show how FFXV will improve on Neo.  Plus with the confirmation that no news on KH3 till winter and that 2.8 is getting a new trailer at TGS, KH will have nothing to show.

most likely showing existing games running better on Neo...

I don't believe Sony has any plans of having existing games run significantly better on the Neo. Some games may incidentally have performance improvements (similar to how Smash 4 runs better on the New 3DS), but unless developers implement a dedicated "Neo Mode" as Sony is mandating for every new game after September 30th, existing games will likely not be able to fully utilize the new hardware. Chances are high that they will still be locked to the specific framerates, resolutions, and textures that they were initially designed to support.

At most Square would only be present to show something developed for the handheld and/or to show how FFXV will improve on Neo.

I am, however, very hopeful for this to be the case. Previously, FFXV fell right outside the window for Neo Mode to be a mandatory inclusion, so I was wary that we wouldn't see it come to pass. Now that it's delayed for another two months, though, it's far more likely that we will get something in that regard.

3:00 AM! I will not be up to then nor wake up that early. I'll be more excited when I wake up the next day.

3:00 PM is much better.

My money's on Tokyo Game Show being the place where we'll see more regarding 2.8, and I think that this time, we'll get the official release date!