If I poke my hand into a balloon, then a camera inside the balloon would show fingers stretching the rubber around them, and at some point you could see through the balloon and it would appear that my hand is inside the balloon. Though it is just that the balloon is shear, around my skin.

The Christ was in this world, even having it wrapped around Him, but He was never OF this world. He was the visible image of an invisible God. God descending from His realm into ours ... taking on the appearance of man ... all the while ... if you looked around the back-side ... you could see that there is a tether to the Father ... like an umbilical chord up to Eternity, and then you would discover that this man standing before me is from above and we are from below. We are of this world, and He is not of this world. He is God with us. His shape / His body ... is the temple of the Father. Jesus is God by the Holy Spirit that is in Him ... God's Life flowing to Him from eternity ... though we see the shell that we call Jesus, so that we can discover what this invisible God is like. We would not be able to see God in any other way.

Here is the mystery. That tether, that chord, was choked off ... so that we could join ourselves to the Christ. Now if you look behind me .. you will see that I have a tether, a umbilical chord stretching up to Jesus Christ the Lord. His Life is my Life. So, that I am no longer of this world, I belong with the Vine. Indeed, it is as I am sitting with Him in the heavenlies, even as I am here on earth. I am part of His body and so are my spiritual brothers and sisters. We are all part of His body on earth ... like branches grafted into a vibrant living vine. Our vital signs are beginning to match His, and the Vine is producing fruit that we might bear. All in accordance to His strength and power, through the Spirit that is within Him and imparted to me, and was that of the Father as the Christ descended into creation (like a hand stretching a membrane of the balloon around it.)

He joined Himself to a Body (the church,) after He was forsaken by the Father (this on the cross.) We pierced Him with our iniquity, but we did not pierce the Father. By His wounds, we are healed. In the near future, Christ with ascend to the Father and consummate His marriage to His purified Bride. I will be with Him and all the other Sheep ... a bride for the wedding. We will dwell in Eternity for the last day will have come and gone, and no more any counting of days.

As we are One with Christ, He will again be one with the Father. Creation will see the last day, and the redeemed will see Eternity.

So, "Did the Son join Himself to and become part of the creation?"
In short ... "Not exactly. He brought forth a harvest of His sown Spirit-seed in the field of creation, through the mystery of godliness which is Christ in us!"