Can I report college classes I intend to take on the Common App?

You can complete the college/uni section in the Education tab, like so:

But, you don’t identify the course there. So, you could identify the course in Current Courses in the Education tab, and choose N/A for course level (since non-dual enrollment college is not an option):

Alternatively, you can just add a note in the addt’l info section with the appropriate info…school, course, timing. As long as it’s somewhere on your app, it’s fine.

If the school requires you to complete the Courses and Grades section, or a SRAR, you will have to include this course in those places as well. Good luck.