You can try. IRCC doesn't like excluding dependent kids, so they may not accept that. It would be better if she could show actual proof of trying to find the child.If she makes a notarized affidavit in my country stating that "she had tried to find the child but could not and since she is not in contact with him from the past 9 years she would like to withdraw her parental rights and that she would never sponsor the child to come to Canada." Will this be a valid document that they would accept?