Can a high school student involved in a college credit program get an arXiv endorsement?
Endorsement is not a service offered by a college, like academic advisement or career placement. Endorsement is an indication that the endorser knows you and believes you are not a crank, or has read your paper and believes it is a reasonably appropriate paper. It's not like just by having a connection to the college, you could automatically be eligible for an endorsement from a professor there.

A program through which high school students can earn college credit does not necessarily give its students increased access to mathematics faculty. So this "connection" may or may not be of use to you in gaining an endorsement. Instead, I recommend reading What to do with research results while being in high school? and How to find an arXiv endorser for suggestions on what to do with your paper, should you choose to write one. The latter explains how to find names of people who are eligible to endorse in a given area. (There may or may not be anyone in the college you are connected to who is eligible in your area.)