8-12 year olds typicaly cannot bypass filters
I hate to be the bearer of bad news, but every filter has an opening. In conversation with someone who had internet in the house at that age, they revealed that they had no trouble at all bypassing OpenDNS and K9, and that was despite their parents being computer literate. And if you let a child have a device of their own, they could always get a more knowledgeable friend to do it for them. No, not every child will, but that still leaves many.
That was half the point. It won’t be every child who skips past the filters and ruins their souls online, but enough will that it’s not worth the risk. And even those with responsible parents, who manage to filter adequately, and limits their use in time and content, still have a huge chance of falling prey to bad friends and negative influences. And that is why it isn’t even a question of weighing up the risks, especially when you consider the enormity of the possible dangers.