Relay

Yes, a switch will be fine.  The radio should have two wires----- one needs constant power (usually yellow), and the other is switched (red).  Be sure you apply your switch to the red wire, so you don't lose your station presets and clock every time.

Also, you should use a small fuse---5 amps ought to do----because if the wiring for your switch ever shorted out, you'd rather blow a fuse instead of melting wires, starting fires, and so on.

Wire the fuse as close to the power source as is practical, then on to your switch, then out of the switch and into the radio.