It is used for Enoch, but only once, in ch.60, whereas it is used repeatedly for the Messiah: see especially
chapters 46, 62-63, and 69.
Yes, in the Book of the Parables (the section in 1 Enoch where this appears) there is this enigmatic, pre-existent heavenly figure called “Son of Man,” who sits on the throne of judgment to destroy the wicked and deliver the righteous - a sort of heavenly viceregent, if you will - and is accompanied by angels. The thing is, in chapter 71 there is a passage where Enoch seems to be addressed with the title, which could imply that he was ‘transformed’ (or perhaps ‘assimilated’?) into this figure. In other words, Enoch the human did not realize it at first, but in the context of the work the “Son of Man” of the earlier chapters was his heavenly ‘alter-ego’ of sorts all along.
And the spirit moved Enoch into the heaven of heavens. And I saw there in the midst of the light how there was something which was built of crystal stone, and between these stones tongues of living fire. And my spirit saw how a fire surrounded this house, on the four sides rivers full of living fire, and how they surrounded this house. And around about were Seraphim and Cherubim and Ophanim; these are they who do not sleep, but guard the throne of his glory. And I saw angels who could not be numbered, a thousand times thousand, and ten thousand times ten thousand, surrounded that house, and Michael and Rufael, Gabriel and Fanuel, and the holy angels who are in the high heavens enter and leave that house. And Michael and Gabriel, Rufael and Fanuel, and many holy angels without number came out of that house; and with them the Head of days, his head white and clean as wool, and his garments beyond description.
And I fell on my face, and all my flesh melted, and my spirit was changed; and I cried with a loud voice, with the spirit of power, and I blessed and honored and exalted. And these blessings, which proceeded from my mouth, were pleasing before that Head of days. And that Head of days came with Michael and Gabriel, Rufael and Fanuel, and with thousands and with ten thousand times thousand angels without number.
And that angel came to me and greeted me with his voice and said to me: “Thou art a son of man who was born to justice, and justice dwells over thee, and the justice of the Head of days will not depart from thee.” And he said to me: “He calls ‘Peace’ unto thee in the name of the world which is to come, for thence peace proceeds since the creation of the world, and thus it will be to thee to eternity and from eternity to eternity. And all who will continue to walk in thy path (thou, whom justice does not leave in eternity), their dwelling-places will be with thee, and they will not be separated from thee in eternity and from eternity to eternity. And so long life will be with that Son of Man, and peace will be to the just, and his right path to the just, in the name of the Lord of the spirits to all eternity.”