Nines seem to pose a bit of a problem for a lot of students but actually it's one of the easiest times tables because there are so many "tricks" you can use to count and multiply by nines.
Here is another video showing yet another way to do it...there are more ways. Here is counting by nines with younger students.
There is a way to use your fingers too. I have to make a short vid on that one too...meantime here is a short post on a simple way to count rapidly by nines.