How can I update a dark panneled room for a teen boy?

You can paint paneling. Use a paint with a primer in it already. Its thicker and covers better. I did it in my basement.

white wash or paint it

You can paint paneling. You can either keep them looking like paneling and just paint, or you can actually fill in the grooves and then paint to make it look like a plain flat wall, here are some links to check out:

https://www.laurengreutman.com/paint-over-wood-paneling/

https://www.todayshomeowner.com/video/how-to-fill-grooves-in-paneling-before-painting/

Paint all lighter colour, or Paint only Central Panels or outer panels and wallpaper interior panels. Or if Shiplap Horizontal - Paint top half lighter or if vertical paneling paint boards Different colours etc...........

It depends on the look you're going for. If you don't mind the grooves of the paneling, take a palm sander to rough up the finish a bit, use a good primer (The Gripper is my favorite) and give 2 coats of primer and then paint. If you don't want the grooves, there are 2 ways to go - you can fill them in with drywall compound and tape (very time consuming) OR you can hang 3/8" sheetrock right over the top (I did this on an old mobile home I was renovating and it worked great!) - then simply paint whatever color your heart desires!

You can put a coat of Kilz paint or a good primer on the paneling and paint it whatever color you like. For easier labor get a good paint so you don't have to apply more than one. Murals are great too for an extra bonus!

i would for sure white wash panels to brighten up and make it bigger all walls