My son has problems breathing from his nose it seems that his nose does not drain i have tried nose spray and seen many doctors he is 9 years old?

Maybe nasal polyp: He should probably see an ENT (ear, nose and throat doctor) to check for a nasal polyp that may be causing him this problem, nasal septum deviation may be the culprit also.

Adenoids?: This sounds like enlarged adenoids. Other less likely possibilities would include a foreign body in the nose or choanal atresia (not having an opening from the back of the nose into the throat).