It seems Alice and Greenfoot are popular in 10th grade (at least where I live). You might start there. There is also a wealth of older programming materials av

It seems Alice and Greenfoot are popular in 10th grade (at least where I live). You might start there. There is also a wealth of older programming materials available for older systems like VIC-20 and C-64. Maybe you could use those with one of the free emulators (Google is your friend). If you want to use a more modern language, I agree that Python is an excellent choice.