Watch the Chord Extensions Pt. 1 online guitar lesson by Brad Carlton from Guitar Lab: The Imaj7 IVm6 Progression
In this lesson, I'll demonstrate adding the 9 to each of the chords. There are two ways to locate the 9(2): It will always be a whole step higher than the root, and a whole step lower than the third. Knowing this enables you to take any chord voicing and modify it to include the 9.