Ketu in 9th house in Astrology is very good as it gives lots of spiritual power, love for religion and very good education.
The 9th House shows interest in religion, long-distance travel, and higher philosophical education. This house rule advance education like PhD or masters, but also the education that brings wisdom in one's life, whether negative or positive, which depends on the planet and signs that rules this house. This house also represents the law field as 9th house is about doing the right things or being punished for it. It's the house of your gurus as in teachers and teachings of your father.
The ninth house starts the third group of 4 houses. Supposedly, the person is settled and is establishing his life purpose at this stage. It is a time for getting deeply tuned to one's Dharma (path) in life. The transformative qualities of the.8th house settle into a coherent pattern in the 9th house. The 9th house corresponds to the upper part of the legs, the thighs. Sagittarius corresponds to the 9th house. The ruler of Sagittarius is Jupiter, adding higher education and fortune to its significations.
Ketu is the south node of the Moon and the rest of the body of Rahu. This is a headless body representing separation, isolation, and the material world's abandonment. This shadow planet represents spirituality, nothingness, and goals that we already achieved in past lives. In this life, we only rely on those things as a last resort.
Ketu in Vedic Astrology is also an unsteady and sometimes treacherous force. Still, its qualities are more of an abstract, inward nature than Rahu, who is more concerned with outward, worldly matters. Ketu can bring hindrance and obstacles in the physical realm of life indicates sparks of intelligence anthe mind's brilliance. The above significations are extremely important to know by heart. You should memorize them, and use them often to remind yourself of the essential nature of the Grahas.
Note: The degree of auspiciousness and inauspiciousness will depend upon a complete analysis of the horoscope (birth-chart).