The argument from people's private lives is fallacious. Because the problem with Sasha Grey's gangbangs is not that she had them but that they are, by her choice, hugely notorious, and they are violent and appalling, and not all nine year olds are supervised online (less likely in a deprived area like Compton) - and yes, beccajoh, it is utterly normal for 9 year olds to look up innocuous details of their day to day life online, they do it all the time.
The other arguments, from bad deeds, different, is totally confused - because YOU are now implicitly equating Sasha Grey's porn career with being a rapist, or a murderer. I'm not. I don't think what she did was immoral, and it wasn't criminal. I simply think it is massively inappropriate for pre pubescent children and I have no inclination to help them to confront it.
Anyway even taking the argument at face value:
What about the footballer offering his date to his footballer friend, who then raped her?
How about the guy who filmed it?
Or the record producer who killed an actress?
Or the actor who killed his wife?
No, I wouldn't want to explain any of that to a nine year old either.