Two questions:
1) Who is the "he" in Dan 9:27?
I believe it refers to "the prince that shall come". The messiah was discussed in v25-26, and then "the prince that shall come" is mentioned. I believe that person is different from the messiah. I believe he is the antichrist. He will initially be seen as a "savior" of sorts, and will set up a covenant of peace, which he will then break half way through the seven year trib.
2) "CONFIRM the covenant". I believe your insistence on sticking with the KJV is harming your understanding. Nearly every other translation says that "a" covenant shall be confirmed, or words to that effect. It does not have to be an existing covenant.
Are you saying Christ broke the covenant 3 1/2 years after it was confirmed? I hope not..