Alcyone is NOT an imaginary place like Xenu or Kolob. In the first place, it is not a planet, but a star. It has only been recently that we have been able to image planets cicling distant stars.
As has been said, Alcyone is one of the stars in the Pleiades star cluster, also known as the seven sisters or M45. It is among the nearest star clusters to Earth and is the cluster most obvious to the naked eye in the night sky, so it was seen by primitive "post-edenic" (yuk yuk yuk) man, and the star cluster found a place in myth and legend - the campfire stories which led to the formation of man's various religions and holy books, so it is not surprising that the Pleiades are mentioned three times in the OT at Job 9:9 and 38:31, as well as Amos 5:8, where they are identified as "kimah" (a cluster).
This may be the inspiration of the popular Apostate term for the Watchtower's NWT translation committee, "kimah fuck." (Started HERE and NOW.)
Siriusly!