I'm replacing the water supplies pipes to a bath and laundry room with CPVC pipe. The pipes will run inside the wood-studded wall.

Do I need to secure the CPVC pipe in some way inside the wall before the stub comes out to a turn-off valve? If so, what are the best options for securing the pipe?

The cross bracing between the studs to secure a stub out is called backing.
Of course you must secure ALL TYPES of water pipes with pipes straps and backing. If you don't secure the pipes in a wall with pipe straps you will have rattling inside the wall and if the stub outs aren't backed and strapped they can be pulled out of the wall. My advice? Strap and secure ALL installations in the wall. Good luck.

John

Thanks, John, that helps.

Are the usual plastic straps, screwed to the backing, sufficient?