The Dm7 and G9 chords are only different by one note in the hand positions I'm giving you here. It's a sweet chord change you can use in many songs and tunes.
When you play along with the jam tracks, play one inversion for four beats and switch to the other inversion for four beats. If these changes feel too fast, play one strum every four beats and then switch inversions. Remember to play through each jam track ten times.