Most Jewish kids miss school twice a year. Once for Yom Kippur, which I believe is the Jewish new year. The other for Rosh Hashana, and I don't remember what that holiday is, or even if I spelled it correctly.
Not sure what the big issue is. When I missed school due to those holidays, I still had to make up any work that was missed. Truth be told, I would have preferred to be in school...and I hated school.
This rule was actually instituted my Junior year in High School. I'd missed 37 days my Sophmore year due to skipping class and what not. If I remember correctly, anything over 13 my Junior year would have led to me losing credit for classes.