Yes you can go to college with out a high school diploma. Look into your local community colleges there is ATB testing available and you can enroll as a not traditional student. However, some states do not allow financial aid to students without their HS diploma or GED. Look around there are many credited schools that can help you and work with you.
You can not attend college without a high school diploma or a GED. It is possible to take college preparatory courses in high school and earn credits towards college, but you will have to graduate to attend there.