My dad was always on his way to work before we got up for school. My mom would get us up when we were little snd send us out the door to catch the bus. She'd take us the the bus stop in the car if it was raining. By 10 or so we were setting our own alarms and getting up to get ready for school, and whichever kid got home first had instructions on what to make for dinner for everyone starting about 6pm or so if mom wasn't able to be home. And my mom didn't even have a full time job, just a lot of taking kids to various places after school. I had friends with parents who both worked and it was no big deal.
Kids are plenty capable to be independent if they are taught to be so and given increasing levels of responsibility and accountability. Kids aren't less intelligent than adults, just less wise and experienced.