@tweeter604, yes, the Swivel Clip, Floating Hand Grip and Suction Mount will work with the HERO9 Black.
The HERO9 Black is bigger compared to previous HERO camera models. It has its own battery and Dual Battery Charger, housing, Media Mod, Floaty, Sleeve + Lanyard, and lens filter. The rest of your GoPro mounts and accessories (e.g. Head Strap, Chesty, Wrist Mount, etc.) are compatible with the HERO9 Black.