AdamsDad,

We've got a city playgroup in Chicago that you'd enjoy. If you haven't already, look us up under local groups and sign up with Chicago Dads. Tomorrow (Thurs.) we're going to Holstein Park in Bucktown which has infant swings and a spongy rubber covering on the ground that is good for crawling.

Once the weather turns nasty, we head to these spots:
Pritzker Children's indoor building at the zoo (FREE although parking is $$$)
Garfield Conservatory has a small baby area (FREE)
Notaebart Nature museum in LP has a great crawling area for kids on the north side of the first floor (FREE on Thurs.)

Cheers,
Jim

I would look for classes and playgroups in your neighbourhood as well.
You will meet other parents and build a network and your kid will enjoy seeing new people too. Lots of sights, sounds and touches meeting the rest of the human race. In Edgewater there are playgroups and music classes held at Emmanuel Lutheran (Greenview and Elmdale).
Over the Winter there are lots of free days at the various museums some of which are better set up for babies than others. The ones Jim mentioned are particularly good. Honestly I don't think a nine month old requires a huge amount of stimulation, or at least not much more than is provided by a stroll around the neighbourhood and some time at the park. I would put your mental health first, your kid will have a blast just visiting the market and checking out the peaches.