When I brought Aleks to school last year, about mid-year, the Principle took a couple of days to see how it aligns with state curriculum - she did not see a problem.

A suggested way in, which worked in our case - are there any other kids who are currently bored in that math class? Get those parents on board - school might be easier to be persuaded if there is more than one kid asking for it. We had 5 kids doing Aleks at school last year - all 4th graders. To make it work, parents had to voulnteer to come to school during math class and supervise those 5 in the lab. Three of us were able to do it, but after a couple of months only two parents remained on board, so I started coming twice a week. This way my daughter (and 4 other kids) was able to work on Aleks 3 x weekly.
Aleks purchased by school is very inexpensive.