The 9th house represents your experiences with long-distance travel, higher education, philosophy and mental expansion. Also, law and publishing.
How you learn, how your mind has grown over the years and education in general falls under the 9th house, ruled by exploratory and intuitive Sagittarius. Your religion, philosophies and spirituality is represented here, as is the way in which you seek out freedom and individuality. It's where you broaden your horizons!
Your birth chart is divided into 12 "houses" which govern specific areas of your life. At the time of your birth, each planet was located in a particular astrological sign and in one of the 12 houses.