The Ninth House is similar to the Third House, in the sense that both of these are related to thoughts and to travel. However, the Ninth House is about deeper, more profound thoughts, and about long-distance travel that can have an effect on your life. Moreover, whereas the Third House is about logical thought, the Ninth House is concerned with holistic thinking, and about ideas which expand our consciousness or enable us to grow. It is often called the House of Wisdom. In addition, and linked to the ideas of holistic thinking, it is concerned with dreams and prophecy.
The planets in the Ninth House show the ways in which we are likely to grow and expand our consciousness. For example, Neptune in the Ninth House would indicate growth and expansion through spirituality. However, this might also indicate that this person's attempts at gaining wisdom were a little too vague and imprecisely directed.