I’m a local and took my 9-yr old son on the hop-on-hop-off bus tour for a day trip before school starts up again. We loved it! You learn a ton about the city’s history and the recorded audio is full of funny jokes that he loved. This is a fantastic way to get around the city, spend time at a variety of attractions (museum campus, Millennium Park, Navy Pier, Mag Mile, etc.) or just hop off to try appetizers at a huge variety of restaurants. Highly recommend this excursion!
Also, ignore the few complaints on here about staff. Other than checking in to board, there is almost no interaction with them (what does occur is professional). My guess is that whoever complains might be a bit of a grump in the first place.