Nikon Z9 Mirrorless Camera - Manual (Page 599)

599 A Custom Settings: Fine-Tuning Camera Settings
Choose whether photos can be taken before the camera focuses when
AF-S is selected.
a2: AF-S Priority Selection
G button
U A Custom Settings menu
Option Description
G [ Release ]
Photos can be taken whenever the shutter-release
button is pressed (release priority).
F [ Focus ]
Photos can be taken only when the camera is in
focus (focus priority).