Yes, the Transfiguration was a VISION according to Matthew 17:9
The Bible was Not originally written in King James English.
In the Greek Interlinear the word ' again ' does Not appear. The added word 'again' is a KJV add on.
Yes, I see the KJV was corrected in the NKJV.
Most other translations also say risen/raised from the dead, not
risen again from the dead.
That is an important difference since it changes the meaning. If Jesus was
risen again from the dead that would me an He rose from the dead before, but
until the Son of Man is risen from the dead means that Jesus will be risen from the dead that is in the future, a future resurrection.
Matthew 17:9
KJ21
And as they came down from the mountain, Jesus charged them, saying, “Tell the vision to no man until the Son of Man be risen again from the dead."
NKJV
Now as they came down from the mountain, Jesus commanded them, saying, “Tell the vision to no one until the Son of Man is risen from the dead."
ESV
And as they were coming down the mountain, Jesus commanded them, “Tell no one the vision, until the Son of Man is raised from the dead."
NIV
As they were coming down the mountain, Jesus instructed them, “Don’t tell anyone what you have seen, until the Son of Man has been raised from the dead.”
Jesus rising from the dead would be in a spirit body - 1st Peter 3:18 B
I believe you are correct about that, and the verse below confirms that Jesus was raised in a spirit body, not in a flesh body.
1st Peter 3:18
KJ21
For Christ also hath once suffered for sins, the just for the unjust, that He might bring us to God, being put to death in the flesh, but quickened by the Spirit,
NKJV
For Christ also suffered once for sins, the just for the unjust, that He might bring us to God, being put to death in the flesh but made alive by the Spirit,
NIV
For Christ also suffered once for sins, the righteous for the unrighteous, to bring you to God. He was put to death in the body but made alive in the Spirit.
ESV
For Christ also suffered once for sins, the righteous for the unrighteous, that he might bring us to God, being put to death in the flesh but made alive in the spirit,
God resurrected Jesus back to his pre-human heavenly spirit person body - Hebrews 9:24
Hebrews 9:24
For Christ is not entered into the holy places made with hands, which are the figures of the true; but into heaven itself, now to appear in the presence of God for us:
That concurs with the following verses:
1 Corinthians 15
44 They are buried as natural human bodies, but they will be raised as spiritual bodies. For just as there are natural bodies, there are also spiritual bodies.
50 What I am saying, dear brothers and sisters, is that our physical bodies cannot inherit the Kingdom of God. These dying bodies cannot inherit what will last forever.
Well, since heaven is a holy place that means that Jesus did not enter heaven in a physical body. Of course that would mean that the physical body was not what the disciples saw taken up when they were looking up into the sky:
Acts 1:11 “Men of Galilee,” they said, “why do you stand here looking into the sky? This same Jesus, who has been taken from you into heaven, will come back in the same way you have seen him go into heaven.”