You don't have the option of "including" taxable income on your return if that income has, by law, been "excluded" from taxation.
You are under no obligation to claim a tax credit or tax deduction, but the unemployment compensation exclusion is not a credit or a deduction - it is an exclusion.
The unemployment compensation has already been reported to the IRS as income on Form 1099-G, Federal law states that up to $10,200 of unemployment compensation is "excluded" from tax. You can't decide to ignore that part of the tax law in order to get around the laws applying to the Premium Tax Credit. If that were the case, you could manipulate your AGI by mis-reporting other tax-exempt income (e.g. municipal bonds) or just report cash income that you never received in order to qualify to the PTC.
