Welcome to the board!!
If you CC.. nobody will ever know but you unless you let it show.
Technically... you could be considered as trespassing for violating the posted firearm ban at the mall. It is highly unlikely that it will even happen. Security could show up if a shopper was to report you. Then security would show you to the door.
You can lock your gun up in your car. I would highly encourage you to ALWAYS lock it in a secure container or with a cable lock affixedto the vehicle. If someone does break in.. you do not want them to easily walk off with it.
There are some gun locker sites listed in this board.I am confident someone will post them for you.
I suggest key or mechanical push button. I do not care for battery operated locks. It would suck to have the battery fail when you really need access to your gun.
Here are a few that would interest me. Not that they are the best price.. shop around the Internet before you buy.