Thank you for your question. Yes, the best option would be to start a new and separate return because of 2 major reasons:
1. Your son is 18 or above years of age.
2. Your son is earning his own income.
Unless your son suffers from a physical or mental impairment, CRA doesn’t view him as a dependant. Even if you provide all of his necessities, do his laundry, and drive him everywhere, he’s still not considered an eligible dependant.
Also, as per CRA, the eligible dependent would be:
*However, you can claim the eligible medical expenses for your or your spouse's adult child on the tax returns.
Further, we encourage you to read the following blogs:
CRA: Can you claim the amount for an eligible dependant?
TurboTax:- Who Can I Claim as a Dependant on my Tax Return?
-Why All Working Children Should File A Tax Return.
Thank you for using TurboTax.