The facts that OP has presented thus far do not indicate such a damaging effect.
They poked fun at him for not having a car, that he "enjoys" riding a bus. Nothing wrong with riding a bus, so long as you aren't prone to motion sickness on them. Not defamatory. At least, no more defamatory than saying a Jesse Helms intern is "Most likely to be a Democrat" or that [Susie Q]'s boyfriend is "Most likely to be Mr. [Susie Q.]', which both appeared in my senior yearbook. (Rather tame compared to the previous year's nude photo.)
Please explain how not owning or driving a car is a protected class, akin to race, religion, sexual orientation, etc. Although James Byrd happened to be walking home in Jasper TX when he encountered the men who would murder him, his death was ruled a hate crime because of his race, not his inability to legally drive.
(For the record, I had neither car nor license in high school.)
Furthermore, having your photo NOT appear on the seniors pages is hurtful, but unlikely to incite anyone to violence.
OP can have a hissy fit, but lets reserve talk of "discrimination" for those cases that extend beyond merely juvenile petty pranks.