Here's an actual page from the government explaining the law and even providing the text of the law: https://dcfs.illinois.gov/for-families/safety/preparing-your...
If you follow their advice and your child is ready to reasonably able to be left alone unattended, you can leave even 8-9 year olds unattended for long periods of time. It's not odd for children to be home alone after school for 4-8+ hours.
Your opinion on "CPS" in Illinois (I assume you meant DCFS and not Chicago Public Schools) is based on not understanding a single paragraph of the law that is written to be readable by the general public.
Kids go all over the place in Chicago while under 14 without their parents. It's literally not an issue.