S. RES. 9 is a resolution passed by the Senate to inform the President of the United States about the election of Jackie Barber as the Secretary of the Senate. This is a formal notification required by the Senate to officially acknowledge the election.
Simple Explanation
The Senate wrote a letter to the President to let him know that they chose a new person, Jackie Barber, to be their helper called the Secretary of the Senate. This is just like officially telling the President about their decision.