They (Lord Brahma and the predominating deities of the planets) worshiped the Lord (Vamanadeva) by offering fragrant flowers, water, padya and arghya, sandalwood pulp and aguru pulp, incense, lamps, fused rice, unbroken grains, fruits, roots and sprouts

Expressions researched:
"Lord Brahmā and all the predominating deities of the various planetary systems began to worship Lord Vāmanadeva, their supreme master, who had reduced Himself from His all-pervading form to His original form"

SB Canto 8

Lord Brahmā and all the predominating deities of the various planetary systems began to worship Lord Vāmanadeva, their supreme master, who had reduced Himself from His all-pervading form to His original form.

SB 8.21.5, Translation and Purport:

Lord Brahmā and all the predominating deities of the various planetary systems began to worship Lord Vāmanadeva, their supreme master, who had reduced Himself from His all-pervading form to His original form. They collected all the ingredients and paraphernalia for this worship.

Vāmanadeva first expanded Himself to the universal form and then reduced Himself to the original Vāmana-rūpa. Thus He acted exactly like Lord Kṛṣṇa, who, at the request of Arjuna, first showed His universal form and later resumed His original form as Kṛṣṇa. The Lord can assume any form He likes, but His original form is that of Kṛṣṇa (kṛṣṇas tu bhagavān svayam (SB 1.3.28)). According to the capacity of the devotee, the Lord assumes various forms so that the devotee can handle Him. This is His causeless mercy. When Lord Vāmanadeva resumed His original form, Lord Brahmā and his associates collected various paraphernalia for worship with which to please Him.