Nikon Z 9 Reference Manual page 182

A
Exposure Bracketing
The settings (shutter speed and/or aperture) altered during exposure
bracketing vary with the shooting mode.
Mode
P
S
A
M
1 If [ON] is selected for [ISO sensitivity settings] > [Auto ISO sensitivity
control] in the photo shooting menu, the camera will automatically vary
ISO sensitivity for optimum exposure when the limits of the camera
exposure system are exceeded.
2 If [ON] is selected for [ISO sensitivity settings] > [Auto ISO sensitivity
control] in the photo shooting menu, the camera will vary ISO sensitivity.
3 Use Custom Setting e6 [Auto bracketing (mode M)] to choose whether
the camera varies both shutter speed and aperture or any one of shutter
speed, aperture, and ISO sensitivity when [OFF] is selected for [ISO
sensitivity settings] > [Auto ISO sensitivity control] in the photo
shooting menu.
❚❚ Cancelling Bracketing
To cancel bracketing, press the BKT button and rotate the main
command dial until the number of shots in the bracketing sequence is
zero (0F). The program last in effect will be restored the next time
bracketing is activated. Bracketing can also be cancelled by performing
a two-button reset ( 0 209), although in this case the bracketing
program will not be restored the next time bracketing is activated.
Bracketing
182
Shutter speed and aperture
1
Aperture
1
Shutter speed
2, 3
Shutter speed
Setting
1