Ok, I understand the issue with maturity being a problem in university. This is valid if you mix a 14-16 year old with 20-30 year old. The way the 14-16 year old may be treated by the other older students may cause one type of mental maddening situation. While, at home or vacation & trying to maintain friends who also have to deal with a special unusual situation.
But I think many of us here aren't carefully paying attention to the fact that this kid is 8 years old. In the above case, I expect the 14-16 year old to be shunned and isolated in many ways which can be brutal. But when it comes to the 20-30 year olds being in class with an 8 year old, the equation is truly different and undefined. Yes, the 8 year old will still not be in with any outside older activities, but, I would not expect the 20-30 years olds treating an 8 year old as a younger graduate. Even they must realize they are dealing with a real child 12 years younger and when in front of him, they will behave differently compared to being around a student only 4-5 years younger.
Think along the lines of having a 4 year younger brother, when you were 16, how would you treat them. I have experience here. Now, imagine you are 20 with an 8 year old aged brother. You wont be giving your 8 year old brother the same treatment.
Also, being 8, I don't believe Laurent Simons friends of 7 to 9 year olds will shun him for going to university in the same way a 14 year old's 13-15 year old friends.
So, I say, yes, there will be development issues, but, in this special ultra young 8 year old's case, I don't think it will the nightmare scenario a few here are proposing.