Composite Mars in 9th house:

Mars is the planet of fire, activity and aggressiveness. Mars in the 9th house indicates a strong need to share ideas, philosophies and beliefs. If your ideas are compatible, you will protect them dearly, while trying to convince others to see your point of view. If however, your ideas oppose each other, then you will spend a lot of time arguing. Trying to convince others to accept your beliefs will be met with great resistance. Mars here indicates traveling together extensively, but to be on the safe side, you should exercise caution regarding any and all modes of transportation. Mars also indicates working together in educational or intellectual endeavors as well.

This interpretation is from the Relationship Composite Report.

Do you and  your partner have composite Mars in the 9th? What's it like?