For a child has been born to us, a son given to us, and the authority is upon his shoulder, and the wondrous adviser, the mighty God, the everlasting Father, called his name, "the prince of peace."
This is saying a son is (already given) not one who will come 700 yrs from now but who is alive at that time. Also the government was never upon Jesus shoulders. The KJV changed the words around. The last line is calling call the wondrous adviser, the mighty G-d, the everlasting Father and that G-d called the child Prince of Peace because of the Isaiah 9:6 "That the government may be increased, and of peace there be no end, upon the throne of David..."
Who is the prince?
If one reads Isaiah in context, that really is not difficult to see at all.
while a literal rendition into English may be hard to pinpoint, the contextual use and the Hebrew grammar fit that the phrase refers to praise for a king's title, a play on the king's name and his role to honor God.
Hezekiah's name itself means and refers to the might of or the mighty God.
The KJV renders this to be in the future tense, so as to make it seem like a future prophecy about Jesus
Hezekiah, was a messiah living at the time Isaiah spoke ( remember, in the Tanakh ALL anointed and righteous kings are called moshiach(messiah) anointed..he was the son of King Ahaz led the quick destruction of Assyria at a time when his own kingdom appeared to be lost. Through him the dynasty of David the messiah,was preserved, and whose descendant is prophesied to rule Israel in the "messianic age".