I've been contemplating about getting a new '17 TXL sh-AWD.
Is it possible to shift out of drive and into neutral and vice versa, while the car is in motion?

I recall someone mention his MDX (same 9 speed tranny), needed to be completely stopped to shift into drive after it accidentally ended up in neutral.

 

Have no idea but why would you want to do that?

 

Going by what this person is saying, his wife wasn't able to shift into drive after the car somehow glitched and went into neutral.

This sounds like a SERIOUS problem when you cannot shift into drive, unless you stop the car first, then put into park, and then put into drive.
The problem is due to some bad software flash which is addressed by TSB 15-034.

 

You can shift from drive to neutral while moving. You just need to hold the neutral button down for a few seconds in order for it to shift to neutral. Then just hit the drive button to go back into drive.