How do I get the kids to stop messing with the lights in our room?

Check this link, however, it does require the use of a home hub.

https://support.apple.com/en-us/HT208709#:~:text=Allow%20remote%20access

Edit: My bad. Home hub is only needed for remote access. You can manage users access while you are present at the location.

Also note that selective device sharing is currently not an option in HomeKit. You can only enable and disable users' full access to the "home."

To suggest a feature to Apple, go here > https://www.apple.com/feedback/

1. Delete the "Home" app off their iPhone.
2. Go to Settings > Screen Time > Content & Privacy Restrictions > iTunes & App Store Purchases > Set Installing Apps to Don't Allow.

The tradeoff: The steps above prevents them from downloading all apps. They will also be prevented from using any features of the Home app.

For more information regarding parental controls, visit

Use parental controls on your child's iPhone, iPad, and iPod touch - Apple Support

and

https://www.apple.com/families/

Can you create a separate Home which you don't share with them?

tt2

What device are they using to access the lights? HomeKit through HomePod, Hue app through iPhone, etc?

Sgathaich wrote:

I want them to be able to use it in their room, down stairs etc. Just not mess with our room.

Tell them if they don't stop messing with your room, they lose access to the whole house.