I have one question and no one can seem to give me a straight answer, all I would like to know is: for my JVC; model KW-R930BTS car stereo does the power need to be on to see the clock?
The manual for your radio says there is a setting to control whether the clock is displayed when the unit is off.
It shows something like this (which was from a PDF I can't link to). See the CLOCK DISPLAY section.
You can search for and download the clearer PDF quite easily.
Just by looking at that radio, I would say it "may" have the clock showing all the time with the setting for it, but it most certainly won't be backlit so you probably won't be able to see it in low light conditions.