... I am debating if it would challenge/stimulate him more if he skip grade one and go to second grade next school year.
Welcome! Possibly your post is more about weighing the pros and cons of grade acceleration, rather than about the test results?
Hoagies Gifted Education Page has a list of resources on acceleration, here:
http://www.hoagiesgifted.org/acceleration.htm The Iowa Acceleration Scale (IAS) is a meaningful guide for considering different factors to determine the likelihood of a positive experience with a grade skip.
http://www.hoagiesgifted.org/iowa_accel_scale.htm
