My thought on this is that parents shouldn't be giving 9 year olds accounts on any online service. But that doesn't seem to be something that is manageable for parents (no judgement). Would it make more sense for the government to completely ban children under x years from using phones/tablets? The internet? It sounds ridiculous but if an adult provided a child with alcohol or tobacco they would face consequences and therefore those things are controlled to a large extent. Could we do something similar in the digital world? Banning it at the website level is futile so maybe taking a step back to the devices themselves is the solution.