All modern radios have some battery drain to maintain basic functions such as the clock, radio pre-sets and other functions when the vehicle is off. A parasitic drain of .05 A or less is considered typical.
To make it clear, no, I did not wire directly to the fuse box. I followed recommended wiring instructions and used wiring harnesses from Crutchfield.
After performing a parasitic diagnostic, I found that something behind the fuse for the radio is pulling .176 A drain when the vehicle is off which is a little over 3 times what is considered normal.
I bought the vehicle used, so I don't know if there was something else modified before I purchased. I will be consulting the wiring diagram and further troubleshooting next weekend.
If anyone knows of the amperage from their head unit (8200) when the vehicle is off, I would find that very useful.