Is there a way I can get college credits for my JST without completing a semester at college?

SPC (Join to see) please take some advice from an old Soldier. If you have the chance to take college courses, and to get your education while you are in the Army, please do it. Take it from a guy that is in school right now to finish a degree, THERE IS LIFE AFTER THE ARMY.
Pick something that you would be very happy doing after you retire from the Army, and get the degree you will need for it.
After you spend a career in the Army. After you do what you are ordered to so for 20+ years, spend the rest of your life doing something that you enjoy.
I served my career and retired, went into the firearms industry and enjoyed that, now I am back in school to be a PTSD Counselor. I wish I had finished the Psychology Degree on Army tuition assistance.
Good Luck son, and thank you for standing on a wall, and saying "Nothing is going to happen to you tonight, not on my watch." (With credit to the writers of "A Few Good Men")

While most colleges are not for profit, all of them are in the business of accepting your tuition money to provide you with a transcript of courses completed.
Your JST is a transcript to be used as a transfer transcript upon enrollment in a college program.
You do have to enroll in a college in order for that college to grant credit for anything on your JST.