That's over the entire population, which includes the elderly. For the 18-34yo block, it's 8.3%, and you'd probably expect it even lower for ... well, the population that, to put it bluntly, succeeded in life enough to get into Stanford.

https://www.census.gov/library/visualizations/2024/comm/disa...

Edit: And to clarify, just to be fair, I can accept there are many things that would qualify as "a disability that the education system should care about" but which don't rise to the level of the hard binary classification of "disabled" that would show up in government stats. I'm just saying that the overall 25% figure isn't quite applicable here.