A Master's would probably be required. A Master's in school counseling would probably be preferred.
You probably need to be Illinois licensed or license-eligible as a psychologist, clinical social worker, counselor, or marriage and family therapist. All these require at least a Master's.
Go to http://www.idfpr.com/DPR/
to see all the crap the state of Illinois licenses and the requirements for each.
Also, a college in Chicago that offers Master's degrees in school counseling is Roosevelt University, located at:
You need to know about college admissions, substance abuse counseling, and all kinds of stuff kids will need help with and a counseling/counseling psychology/school counseling degree probably best balances these issues.