Taking a Year off to improve my Act scores

Can i take a gap year from junior year before entering senior year? I know i can take a gap year after senior year. Is it a good decision

Good*

Is it possible for a student in the U.S to do this? I am looking to improve my act by 7 points to be in the 34-35 range but do not have sufficent time to do so as i am taking all Ib and Ap classes and maintaining a 4.0 and particpating in extra circulars, and i feel as though i cant focus on the Act unless i am away from schoolwork and get sufficent sleep and minimum time free time to improve my score