Welcome!
For the past decade or more the gold standard in grade skipping has been the Iowa Acceleration Scale (IAS). Info here -
http://www.davidsongifted.org/db/Articles_id_10053.aspxm I'm familiar with up to 4 years of successful grade acceleration.
Some positive grade skip stories here:
http://www.davidsongifted.org/db/Articles_id_10651.aspx Genius Denied here -
http://www.geniusdenied.com/Have you talked to your son about the grade skip?
There are several recent threads on acceleration, including
http://giftedissues.davidsongifted.org/BB/ubbthreads.php/topics/171927/1.html There are also threads especially about boys skipping a grade, including
http://giftedissues.davidsongifted.org/BB/ubbthreads.php/topics/137899/1.html