Plenty of YouTube videos that discuss the main video setting choices and why. Most available video settings are common across camera brands/models and not specific to just the Z9.
Camera video settings decisions should be based on the intended final video target usage - i.e. web viewing/YouTube, etc. or edited into other videos, broadcast, etc.
4K UHD 3840x2160 and 1080 HD 1920x1080 in 16:9 format are probably the most common.
Frame rate/frames-per-second/fps, and their shutter speed recommendations are related to the often mentioned & supposedly desirable "cinematic look" and motion blur. There's videos showing the motion blur differences for different frame rates.
24fps and 30/29.97fps are common in the US when slow-motion is not planned - 60/120/240fps if wanting to create slo-mo in post-production.
Shallow DOF/better Bokeh/subject-background isolation is usually desirable for video much like stills - so wider apertures used.
Given the above a variable neutral density/VND filter of around 2-8 or 2-6 stops is needed when using slower shutter speeds with wider apertures for 24/30 fps especially in most outside daytime shooting environments. So far I've not done any slo-mo so I use 24 or 29.97fps and my VND's pretty much live on the lenses used for shooting video. Even at 60/120fps a VND probably needed.