tān rocamānān sva-rucā
brahma-putropamān nava
papraccha parama-prītaḥ
praśrayāvanato nṛpaḥ
tan -- them; rocamanan -- glowing; sva-ruca -- by their own effulgence; brahma-putra-upaman -- just like the sons of Brahma; nava -- nine; papraccha -- he asked; parama-pritah -- transcendentally overjoyed; prasraya -- with humility; avanatah -- bowed down; nripah -- the King.
Srila Sridhara Svami has pointed out that the word sva-ruca indicates that the nava-yogendras glowed from their own spiritual effulgence and not due to their ornaments or any other cause. The Supreme Soul, Lord Krishna, is the original source of all light. His brilliantly glowing body is the source of the all-pervading brahmajyoti, the immeasurable spiritual light that is the resting place of innumerable universes (yasya prabha prabhavato jagad-anda-koti [Bs. 5.40]). The individual soul, being part and parcel of the Lord, is also self-effulgent. In fact, everything in the kingdom of God is self-effulgent, as described in Bhagavad-gita (15.6):
na tad bhasayate suryo
na sasanko na pavakah
yad gatva na nivartante
tad dhama paramam mama
It has already been described in many ways that the nava-yogendras were pure devotees of the Lord. Being completely Krishna conscious souls, they naturally radiated the intense effulgence of the soul, as indicated here by the word sva-ruca. Srila Sridhara Svami has also pointed out that the word brahma-putropaman, meaning "equal to the sons of Brahma," indicates that the nava-yogendras were on the same spiritual platform as the four exalted Kumara brothers. It has been described in the Fourth Canto that Maharaja Prithu received the four Kumaras with great love and reverence, and here King Nimi is similarly receiving the nine sons of Lord Rishabhadeva. Receiving exalted Vaishnavas with love and reverence is standard spiritual etiquette for those who desire progress and happiness in life.