Under 13, no. Paragraph 3 of the Open Beta Agreement states you must be 13 and over to participate in the Home Open Beta: http://manuals.playstation.net/document/ps3-eula/p
1) This is not a tech/support issue. It is a Development and what the community wants issue and should be in Home General.
2) There have already been two heated discussions on this. If you'd like, you can read them in The Borat swimsuits and Tempest_Fire 13+ Discussion. Both thread are now lockeddue to having run their course (participants were becoming very rude and the topic had become derailed) , but can still be viewed.
This has already been discussed in a previous locked thread.