Review on SRUIM Waterproof Case for GoPro Hero 9: Underwater Diving 50M Protective Housing Shell with Bracket Accessories by William Turner

That's it. There are many on the market at reasonable prices, some cheaper than this one. Good quality. Mandatory for actions that may damage the camera. I would recommend getting a kit that includes other items such as a swivel clamp, float, underwater filter glasses, bag, possibly a head harness and a chest strap. Third-party suction cups are only useful for installation in low-impact (in-vehicle) situations. Kupton also sells these kits.