I could not find any thing in rules that said it was illegal. I know some tournys say they dont want this done in flyer. I know some wrestlers do this. My 8 year old has been wanting to wrestle up for two years now. I would not let him last year. I think he could compete with the 10U this year.
Rule 4
Competition shall be in the following age and weight classes. Age determination shall be as of midnight, August 31 for that competitive year. For example, a child with a birthday on August 31, 1997 will wrestle as an eleven-year-old during the 2008/09 season. A child born on September 1, 1997 will wrestle as a ten-year-old during the 2008/09 season. Any USAWA-Kansas Kids club may challenge the age of any wrestler during weigh-in at a sanctioned tournament. The wrestler or the wrestler's club must, within one week, provide a birth certificate or similarly reliable verification that the wrestler's age stated on his/her membership card is accurate.
The age divisions are:
Eight and Under
Nine and Ten
Eleven and Twelve
Thirteen and Fourteen
Fifteen and Sixteen
The rules do not provide for an eight year old to wrestle up an age division.