Apart from any other divisional chart, Navamsa is far superior and stays very close to the D1 chart or Rashi chart because of its unique calculation method. Once the D1 chart is prepared, then its planetary quality and dignity are primarily confirmed from the D9 chart only. And so for this reason alone, it is very much recommended to check yoga formations in the Navamsa chart. A specific yoga if present in both D1 and D9 charts gives more chances that its results will be seen in one’s life more prominently.
There are some yogas like Kalpadruma yoga where specific planetary combinations need to be present in both Rashi and navamsa charts. In this case, the yoga itself is defined in a way to be more specific by including navamsa.
Let's take an example of Mahapurush Yogas:
Think of a scenario where Mars is a functional malefic planet in a person’s D1 chart and is also occupying a bad house there. In the Navamsa chart of the same person, Mars became a functional benefic and Yoga karaka planet (Cancer ascendant) and created a Ruchaka yoga (panchmahapurush yoga). Here the native will not feel the greatness of Panchmahapurush yoga, but will definitely get positive benefits of Mars in his /her life, especially after his/her marriage.
In another scenario, where Venus is occupying a Kendra/trikon / exaltation or friendly house for Capricorn ascendant person where Venus becomes a yoga karaka planet. In the navamsa of the same person, Venus is forming Malavya Yoga (Another Panchamahapurush yoga). Now here, the native will definitely get the results of Malavya yoga in his / her late 30s because Navamsa is confirming the strength and quality of an already benefic planet through a panchmahapurush yoga.