There are a few options for parental controls for Amazon Alexa. The Reason ONE device itself does not have any parental controls as the Alexa voice assistant is under Amazon's control.
To access Alexa settings, you need to download the Amazon Alexa app on your mobile device and sign in to your Amazon account.
For Music & Podcasts, there is an explicit language filter that you can enable, which should block any radio stations and Amazon Music songs that have explicit language. On the Alexa app, tap the three bar icon at the bottom right labelled More, then scroll down and tap Settings. Scroll down to Music & Podcasts, then select Explicit Language Filter. You can enable the Explicit Filter by tapping the toggle icon to turn it blue.
You can also disable Voice Purchasing, which will prevent accidental purchases of different services or products from Amazon. On the Alexa app, tap the three bar icon at the bottom right labelled More, then scroll down and tap Settings. Then go to Account Settings and tap Voice Purchasing. Then tap the toggle to turn it gray, which means Voice Purchasing is turned off. Even when Voice Purchasing is turned off, searching for products and adding them to your Amazon shopping cart is still possible via voice control.
There's also a service called Amazon FreeTime, which allows parents to create a more personalized experience for their children and control what content their children can access. However, this service is currently limited to Amazon Echo devices and does not work with the Reason ONE clock.