A:AnswerYes, you can use the Max Lens Mod with both the HERO9 Black and the HERO10 Black. Note though that the HERO10 Black will need an update to use the Max Lens Mod. That update is expected to be out on November 16, 2021.
A:AnswerThe Max Lens Mod is designed to improve stabilization and to expand the field of view even wider than you'd normally get with the GoPro. It is not going to improve the zoom capabilities though.
A:AnswerYou do not need to remove the Max Lens Mod to use the camera with the Media Mod. You can keep the Max Lens Mod on the camera while you use the Media Mod, and while you connect or disconnect the camera from the Media Mod.
A:AnswerWhen the Max Lens Mod is attached, the camera will not fit into the protective housing. If you plan to take your GoPro diving, the best option would be to use it in the protective housing without the Max Lens Mod attached.
A:AnswerWhen shooting in Max Lens mode, the maximum resolution on the HERO9 Black is going to be 2.7K. You can select from a few field of view options in this setting though to frame the image.