If Mercury is in the 9th house the native will have many children. He will be learned in Vedas and Shastras, fond of music, very patient, religious minded, full of glory, wealthy and fortunate and his father will be long-lived. He will be well cultured and will take interest in meditation.
The mind will tend to be filled with abstract thoughts rather than specifics. People with this placement can explain the general principles of why something works, but they have trouble making actual repairs. The general philosophy of life comes under constant scrutiny. Mercury loves to analyze. However, there will be little emotional commitment to those general principles. To Mercury, one idea is as good as another.
Other Views
Brihat Jatak- The person concerned will be endowed with children, wealth and happiness.
Phaldeepika- The native will be very learned, religious minded wealthy and of good conduct.
Saravali- The native will be very wealthy, very learned, of good conduct, orator, proficient in his work and religious minded.
Chamatkar Chintamani- The native will be religious minded and very wise. He will perform religious rites, bathe in the Ganges, bring good reputation to his family and will destroy those who indulge in sinful deeds.