Is a OBD2 Power adapter for my Dash CAM safe to use to power the Dash CAM?

Not really a good idea to plug anything into the OBD port unless it's a scan tool. That is because they are not intended for that use and there are a number of items that can really cause problems if they short out or send odd signals into the port. It is far better if you need power would be to install something like attached to get power and charging ports for other items. These were just quick amazon searches but if attached to a fused power like the OE cigar lighter or power socket it would give you more options.

Good choice. I've seen multiple odd issues when things were plugged into the ports. Those insurance monitors, "fuel savers" and even the cheaper test dongles. It's almost as bad as aftermarket stereo or remote starters in causing problems.