Low Battery Warning after Battery Replacement

I have 2016 LR4 with 77K miles on it.
I recently got the 'Low Battery' and 'Charging System Fault' warnings when driving home from work. Thankfully I was close to home. I removed the battery and got it tested/replaced. After I put the new battery in, the vehicle would not start. Only the running lights would come on, along with a few internal lights. When I hooked a battery charger up to the 'new' battery, it gave a battery % of 9% and voltage was around 8.5.
After charging up the new battery I got the vehicle to start, but received 'Charging System Fault', 'Transmission Fault', 'ABS Fault'. When I turn the vehicle off the battery % goes back to 9% and I have to charge it for two hours to start it again.

Is this an alternator/starter issue? Or just is the vehicle computer just out of whack?

I read a few other posts about the 'Charging System Fault', but everyone seems to be in the clear with a new battery.

If you have a multimeter, check the voltage of the battery when the vehicle is running. Should be around 14 volts.

Where did you buy your new battery? Seems like it wasn't charged. 8.5 volts is really really low for a car battery.

I would start by returning that battery and trying a different one if it was really at 8.5 volts when you bought it.

As suggested above & not forgetting that you will need to reset the vehicle charging system in order that system recognises the new battery and doesn’t try & charge it based on the info it retains on the old battery.

Screenshot below shows some other threads that will probably explain better than I!

PS: Happy 4th of July to all US members