I would not trust anyone to be my spiritual leader unless I was convinced he could honestly say the Christ Spirit dwelt in him.
How could you or anyone else here pretend to know what happened 2000 years ago? Were you there to observe things? I tell you that that at first we do not know. We hope and believe it may be possible. We do not have the "Spirit of Truth" to know such a thing; but if the Spirit of Truth has come, we can honestly say that we know the Spirit is in us and thus it is very believable that the same Spirit came in the flesh for Jesus.
Now you have said Jesus "is" God. Let's read on in 1 John 4.
1Jo 4:12 No man hath seen God at any time. If we love one another, God dwelleth in us, and his love is perfected in us.
People saw Jesus. Go figure. That tells me something.
1Co 8:6 But to us there is but one God, the Father, of whom are all things, and we in him; and one Lord Jesus Christ, by whom are all things, and we by him.
Back to John where the present tense is also used in places:
13 Hereby know we that we dwell in him, and he in us, because he hath given us of his Spirit.
14 And we have seen and do testify that the Father sent the Son to be the Saviour of the world.
15 Whosoever shall confess that Jesus is the Son of God, God dwelleth in him, and he in God.
16 And we have known and believed the love that God hath to us. God is love; and he that dwelleth in love dwelleth in God, and God in him.
It is scarcely enough for someone with unclean lips to mouth some words without understanding and correct intention. People can lie. That is not a true confession. What good would it do anyone to say he believes the Christ Spirit was in Jesus if he doesn't pursue the matter so the Spirit also resides in him? The correct type of confession about Jesus means also that God will dwell in the person confessing. There is an incorrect sort.
Mat 7:21 Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Father which is in heaven.
And I would say the easiest way to tell if you or I or anyone else has the Spirit is to look at our works. If we are filled with the Spirit and obedient to the Spirit's direction, it will show up one way or another. Love is not something that is kept bottled up. If God is present and acting through someone, we should see something good.
Jas 2:26 For as the body without the spirit is dead, so faith without works is dead also.
The Christ Spirit made it possible for Jesus to do the Father's works, and it is possible for us to do the same. It will do us no good to believe the Spirit of God was in Jesus if we can't believe the same Spirit can be in us.