But Matthew wrote this account many years later when all things had been revealed to him.
"But when the crowds saw this, they were awestruck, and glorified God, who had given such authority to men." Matthew 9:8.
The first part of this sentence describes the reaction of the crowds, i.e., awestruck and glorifying God. The second part of the sentence, i.e., "who had given such authority to men," is not the observation of the crowds but is a statement of fact supplied by Matthew, who knew that he and the other apostles had been granted the power of absolution.
First, Matthew was one of the first books to be written, ca. 55 A.D.
Secondly, the date doesn't matter that much anyway. Matthew is writing a biography, a history of the life of Christ. One does not give the details of teen-age years while in the midst of giving details of the infant years in a biography, for example. Matthew had knowledge of the resurrection, but that is not the topic here. He is writing of the beginning of the ministry of Christ, not the ending.
The same parallel account is given in Mark
Mark 2:7 Why doth this
man thus speak blasphemies? who can forgive sins but God only?
Mark 2:10-11 But that ye may know that the Son of man hath power on earth to forgive sins, (he saith to the sick of the palsy,) I say unto thee, Arise, and take up thy bed, and go thy way into thine house.
Mark 2:12 And immediately he arose, took up the bed, and went forth before them all; insomuch that they were all amazed, and glorified God, saying, We never saw it on this fashion.
And in Luke::
Luke 5:25-26 And immediately he rose up before them, and took up that whereon he lay, and departed to his own house, glorifying God. And they were all amazed, and they glorified God, and were filled with fear, saying, We have seen strange things to day.
There is nothing in any text that says anything about the power of absolution. The word "men" simply refers to mankind. That is the sense of the Greek, and of the context. The other accounts also refer only to amazement, amazement that is expressed in different ways.