1 Is not a multiple of 9, nothing times 9 is 1.
2 Is not a multiple of 9, nothing times 9 gives 2.
3 Is not a multiple of 9, nothing times 9 gives 3.
6 Is not a multiple of 9, nothing times 9 is 6.
Those numbers are all less than 9.
9 is a multiple of 9 because 9 x 1 = 9.
36 is a multiple of 9 because 9 x 4 = 36.