Do you have any donations to US charities? Generally, you can only claim donations to US charities against US income, or your “world” income if you live on the border and your main source of income is in the US. The exception is if you give to a US university, and it’s either a school on the CRA’s list of “qualified donees” or you have a family member attending that school.
If you don’t have US income, the amounts won’t show up on Schedule 9, but you can see them on the DON worksheet.