To what has already been mentioned, I could only add that it rules all the people who affect or stimulate our growth (teachers, priests, spiritual guides etc)., distant countries but also distant travel, pilgrimage and pilgrims
In Mundane astrology it rules foreign affairs, international law, religion, the Church and all institutions dealing with religious or spiritual matters, colleges, educational institutions, philosophical and scientific institutions but also publishing industry, airlines, sea traffic, world conferences etc.
As a derived 3rd from the 7th, it rules spouses' brothers and sisters.
When examined through the prism of the 3rd/9th axis, in a way, it extends the activities described by the 3rd: if the 3rd is a chit-chat then the 9th is a confession or counceling, if newspapers are the 3rd, heavy books are the 9th etc. Short course / high education, information / knowledge, phone call / travel, hearing something / understanding something etc.
It cadent, diurnal and masculine and the house in which the Sun rejoices.
In medical astrology, it rulers buttocks, hips and thighs.
The colours are green and white.
This house is naturally associated with Jupiter and Sagittarius. You can often find Jupiter inside the 9th in the natal charts of trully religious people. However, don't be surprised if you find a strong activity of well placed and dignified planets inside the 9th in the charts of people who claim to be atheists- healthy planets inside this house push the individuals to think about things represented by the 9th (including religion) and they often have very sound and well ground opinions when it comes to such matters.
The direction is South-south-west.
It also rules the first part of the person's adulthood or late teenage years ( the beginning of the 2nd quarter of life; houses 9,8,7), the 2nd 6 hour period of the day, summer months and choleric temperament.