Yes, the Range Safety Officer could send a coded command to "terminate the flight of an erratic vehicle" by cutting off the engine and "dispersing the propellant". Each of the three stages in the Saturn V rocket had linear shaped charges to blow up the liquid hydrogen and liquid oxygen tanks. [1] The astronauts would hopefully be pulled to safety by the launch escape system, the rocket engine on the top of the capsule.

[1] See https://history.nasa.gov/afj/ap10fj/pdf/19700015780_as-505-a... pages 14-15.

NASA has a page with lots of info about their range safety program: https://kscsma.ksc.nasa.gov/RangeSafety

And yes the rockets had shape charges in each stage which can be activated to destroy the rocket in a controlled fashion. If you have a rocket gone haywire, it's better to jettison the crew capsule to safety and do a controlled demolition, to prevent the rocket from flying out of control and crashing into structures or people on the ground.

This is also why rocket launch sites tend to be coastal locations with ocean to the east - there's a lot less valuable stuff under their flight path.