You will use it many times. Repeat with other combinations. Point out that doubles only have two members in their family. Elicit that because the two addends are the same, the other fact will be exactly the same, so there is only one addition fact. Then ask a volunteer to write the subtraction fact on the chalkboard.
Doubles have only one addition fact and one subtraction fact in their family.
Then introduce the Make a Ten strategy. Point to the 9. First, you can make a 10 by taking 1 from the 5 and adding it to the 9 to make 10. Now you have a 10 and a 4 because you took 1 from the 5. Walk the children through the process as you point out each step that you take.