SINs that begin with a "9" are issued to temporary workers who are neither Canadian citizens nor permanent residents. The use of these SINs is temporary and are valid only until the expiry date indicated on the immigration document authorizing them to work in Canada.
If your SIN begins with a "9", you must update your SIN record to ensure that the expiry date always corresponds with the expiry date on your document from Immigration, Refugees and Citizenship Canada authorizing you to work in Canada.