Gulika (Maandi) is regarded as son of Saturn and is obtained by mathematical calculations only.
nine upagrahas are – Māndi (मान्दि), Yamakantaka (यमकण्टक), Ardhaprahār (अर्द्धप्रहार), Kaal (काल), Dhooma (धूम), Vyatipata (व्यतीपात), Paridhi (परिधि), Indradhanu (इन्द्रधनु) and Upaketu (उपकेतु). Maandi is Gulika (गुलिक). With the exception of Yamakantaka the rest eight upagrahas are malefics and produce bad results. Yamakantaka is powerful in conferring benefits same as Jupiter but the other eight have evil influences in the bhavas (houses) they are found to occupy.
Rahu, Ketu are north and south nodes of moon (shadows) but not planets. Their shadows dont go beyond earth and this so-called planet 9 is said to be outside pluto's orbit.
Outder planets, Uranus, Neptune, plutos were mentioned by Veda Vyas in Mahabharata as Sweta, Syama, Teekshana
, but being too far and taking lot of time to revolve around sun, their effects were not considered as human lives are smaller to experience their actual effect. But there is still some effect.
For example, Saturn takes 29½ years to complete 1 revolution around sun (that is one complete zodiac cycle).
So, a human can experience 2 or 3 saturn returns in his life time and saturn transits each sign for approximately 3 years.
Where as uranus takes 84 years and many humans will not see a uranus return in their life time. Also 7 years transit in each sign is too long.
Neptune (164 years), Pluto (248 years) can be ruled out for predicting human lives.
However, their retrograde periods and transits can be useful in making world predictions like huge wars, technological innovations, new viral diseases (basically caused by comets from outer space who drop in new viruses into our atmosphere while coming from other galaxy) etc.
Planet 9 (if exists) is none of these.
Actually what scientists have discovered now is that planets have gravity waves. Earlier, they didnt believe in astrology and argued that a planet far off from earth cannot influence events over here.