You cannot include your son's earnings on your tax return. If he is required to file, he has to file his own tax return.
If you can claim your son as a dependent, he does have to file a tax return. But it looks like you probably cannot claim him because he made more than $4,050, unless his income was from a sheltered workshop. If you cannot claim him as a dependent, and he got a W-2 for the $8,800, and that is his only income for the year, then he does not have to file a tax return. If income tax was withheld from his pay, he might want to file even if he is not required to, in order to get a refund of the tax that was withheld.
You didn't say how he made the $8,800. If it's self-employment income, in box 7 of a Form 1099-MISC or not reported on any form, he has to file a tax return in any case.
If you can claim him as a dependent and he does file a tax return, make sure he indicates on his tax return that he can be claimed as a dependent by someone else.
