Hmm..
After looking at the owners manual there is no mention of powering up or powering down the unit manaully?? Generally there will be some button that you push and hold to turn radios on/off with..
You can check out the owners manual
HEREThe remote has a power button but mentions turning On/Off the "source"??
Pulling the main fuse may turn it off, but depending on how this unit is wired may dump everything you have preset in memory by doing so.
The better solution is to find the "ACC" wire on the radio (red wire per the manual on page 28) and cutting that wire and adding a manual On/Off switch.
The switch now simulates the ignition switch of an automobile installation.
Do not cut and switch the yellow wire, that wire must be unswitched and is used to keep the radio memory and your sound settings alive.