The whole family received their own Fire 8 for Christmas and all share the same Amazon account, is there a privacy setting for each device so the content is not shared (books, magazines, etc)? Thanks
No, in general, all devices that are registered to the same account will have access to all of the content in that account (as well as the payment method, order history, etc.)
If you have young children, you can use FreeTime child profiles to limit what can be viewed/accessed. Otherwise, you'll need separate accounts if you want privacy.