I had exactely the same cracking plastic sound rattle at the same position. It was driving me crazy also. It was worse for me when the car was under the sun some for a while.
The sound came from the top of the dash where the two part meets.

What I did is I pulled back on the plastic part that meets with the window using my fingers and since then I have not heard any noise from there since.
When I was pulling on the part I could hear the rattle sound. By playing with the part I guess I put it back in position and the sound disapeared.

At the beginning I was sure that the sound was coming from the glove box but it was not the case.