From my perspective it is supported but not enabled. It is supported as a feature on the Lumia 930. So why not the 929... I just updated my ICON back to Windows 10 Mobile to check things out.
With version 10.0.10586.107 it includes the system registry keys needed:
HKLM\SYSTEM\Touch\Setting\WakeupGestureSupported and HKLM\SYSTEM\Touch\Setting\FF\EnableWakeupGesture but they are both set to 0. I set them both to 1 and then added the key below:
HKLM\SOFTWARE\OEM\NOKIA\Touch\WakeupGesture\
"Enabled"=dword:00000001
However, I am having an issue enabling it. I tried this twice and had no touch at all each time I rebooted the phone. I thought my display is getting ready to go bad. This Lumia ICON I have has taken a beating so it seemed likely. Yet after a hard reset it even hung there with touch at all available, but after about 5 min it came to and I was able to navigate the phone again. I will let you know if I eventually get it to work or not.