Can I submit my application before fall semester grades are released?
You certainly can do so—many students must, given that the deadline at many schools is before the fall semester is complete. 

However, note that any school that accepts you will want to see your finished transcript before allowing you to enroll. Significant plummets in grade (going from an A average to a C average in your final year, for instance) will raise eyebrows, and potentially cause some schools to withdraw offers.