Yes, there still is approx. 4mm left at infinity focus. Thus just the clearance required for the shutter cover curtain of the Z9. On the other Z/FX, with mechanical shutters, infinity focus also works if one is careful. Just hand-holding the lens in front doesn't work well as the danger of scratching the sensor is very high. Once the lens is "locked" through the Z bayonet on the adapter, the danger evaporates.
All X-Ray Heligon & Oude Delft fans: despair not. The new adapter still allows close focus and super-blurry images !!!