Sounds kind of like my oldest DS (now 10 years old!). He used to love the mall and the mall play areas - just loved being around all of the other people and really liked the interaction. I did do some Gymboree - he loved it, but also found similar classes done through the local rec center that were active and engaging enough. He ended up liking music classes a fair amount also, but generally the ones that had lots of movement. Little Gym ended up being a big hit, but 9 months might still be a little young for that. He liked the toddler area in our local science center a lot - still loves science. My youngest son loved classes at the zoo and nature centers - not sure on what age those start though - I would look out for ones that say family though - probably not intended for 9 months, but could work. Good luck.
