I'm going to tell a kid he needs to have better hygiene
What do you mean by that? Is he always dirty?
I've seen him on the bus putting his dirty feet up on the seat. He also has some sort of body odor issue going on.
While it's understandable to be upset at someone for being unhygienic in public as they can track dirt and smell offensive, it isn't right to directly call that person out. It can be publicly humiliating and hurtful to have one's hygiene called into question.  You should try to tell the person privately and tactfully that he needs to clean himself better as his hygiene is starting to affect others.
I'm willing to have a discussion until I find another solution.
That is fair. You need to do it respectfully but you should say something because it is bad to have poor hygeine.