The Father himself is speaking in Hebrews 1 and says in verse 8 that Jesus, His Son, is to be called God as well. Now, Colossians 2:9 makes sense. "For in him dwelleth all the fulness of the Godhead bodily." Verse 8 then says not to follow the philosophy and vain deceit after the traditions of men. This means to only follow prophets and apostles who teach through the spirit of God and not the secular non-prophets of the Unitarians like Jehovah Witnesses and their non-prophet so called scholars.
As Jesus Himself said in John 10: "
Do not believe me unless I do the works of my Father.
But if I do them, even though you do not believe me, believe the works, that you may know and understand that the Father is in me, and I in the Father.”
And the Gospel of John opens with the words:
1 In the beginning was the Word, and the Word was with God, and the Word was God.
2 He was with God in the beginning.
3 Through him all things were made; without him nothing was made that has been made. . . .
. . .
14 The Word became flesh and made his dwelling among us. We have seen his glory, the glory of the one and only Son, who came from the Father, full of grace and truth.
15 (John testified concerning him. He cried out, saying, “This is the one I spoke about when I said, ‘He who comes after me has surpassed me because he was before me.’ ”)
I think the New Testament writers accepted that Jesus was God with us for his short time on Earth, and Jesus was/is God. I also think those who believe God the Father and Jesus the Son are two separate beings are okay with God who doesn't care all that much about our theology. He cares more about our love for Him and others that He has created, our willingness to do good, to be a blessing, follow His leading via the Holy Spirit, to be His witness for the time we have here on Planet Earth.