What is a easy way to remember your nine facts

Use your fingers.

Hold down the first finger on your left hand, nine fingers remain up. The answer is 9

For two hold down the second finger on your left hand. On the left is one finger standing, and on the right are 8 fingers standing. The answer is 18

This pattern works for everything up to ten. Then you remember 9 x 11 is 99. And 9 x 12 is 108