IF they turn 19 BEFORE Aug 1st 09(Jan 1st is not and never has been the date to my knowldge) then you are 100% correct and they (whoever they are) would be inelegable for the 09 season.

That being said anyone who starts school at 5 would be able to holdback/fail a grade and still not be 19 before that date

i.e my sons Birthday is Sep 30 he will start school when he is 5 and will turn 6 that same year (1) If he finishes school without failing OR holding back then he will start his senior year at 17 and turn 18 that same year (2) If he Holdsback/Fails 1 year then he will start his last year at 18 and turn 19 that year and still be elegable (3) If he holdsback/fails 2 years he will be 19 on Aug 1st and be inelegable