The Circle is the Interstate Highway intersection of 90, 94, and 290 which is a major traffic bottleneck.
The check engine light would illuminate.
Chicago to Pittsburgh is about 7 hours. Try a map site for specifics.
If you already have a learner's permit in Texas there is no need to take the learner's test in Chicago unless you plan to move there and be a licensed driver in the state of Illinois.
It is mandatory in California.
It's a number the department assigns to that vehicle for their department records.
approx. 1 hour depending on traffic
There are a number of resources that one can use to find a list of free things to do in Chicago. For instance, Enjoy Illinois, National Geographic, and Things to do in Chicago all list free things to do in Chicago.
It is 967 miles according to Google Maps.