I just got a Hero 9 and an Enduro battery. It came with a USB cable but nothing to connect that cable to the wall socket. I had thought that I could charge it with the computer, but apparently that's not recommended, as the laptop I had wouldn't (I was told) provide enough power. I also thought that perhaps GoPro would sell what I needed, but apparently their SuperCharger isn't available, or at least not for the Hero 9.
The GoPro site says I need something that provides 5V and 2A. I've tried to find that, but am having difficulty. I went to some local stores, but was told that what they had was meant for mobile phones and would provide "too high" a wattage for a GoPro, and would damage it and/or the batteries. The components that I found -- the ones that plug into the wall socket and have a spot to plug in the USB cable -- all were something like 15 to 20W. I have no idea what I'm looking for in terms of wattage.
I would think that GoPro would provide a complete solution for charging their batteries. Any suggestions much appreciated!