whatever we do, our kids always know better than we about these things, or they have friends who know a lot about these things
if you put a program, your kid will find a way to penetrate it
if you put the in a common place, your kid will find a way to hide himself from the eyes
nothing will help you than a self protection
but if you insist on, you can do a thing:
all computer save the web site on a folder, so try to find that folder, and look at its contents every day, or every to or three days
tell him that you can know the site he visit, so he must be careful. but don't tell him about the folder, so he will not empty its contents
this is a method, but your kid will found a way to penetrate it, so nothing like self protection