Hi, Welcome to Health care magic forum.
As you describe it appears that he has the
refractive error of the eye, he is 14 years, and have the problem since 9 months means there is no possibility of the migrine.
It could be refractive error, or
anxiety due to the incresed syllabus of higher classes.
I advise you to consult an ophthalmologist for diagnosis and treatment.
I usually prescribe to my patient with such symptoms alprazolam 25mg, at bed time,along with other medicines and spectacles if necesory.
Give more of green leafy vegetables, pulses, sprouts, and protein rich foods to have a good general health.
Wishing for a quick and complete recovery. Thank you.