9. Their wings were joined one to another; they turned not when they went; they went every one straight forward.
He is not saying that the wings of one creature are joined to the wings of another creature. He is saying that each wing is joined to another wing, not directly to the creature.
The second and third parts of this verse present a mystery. We do not know what the "theys" refer to. There are three "theys" in this verse, one after another and we are given very few clues to which refer to creatures and which refer to wings. The first "they" most likely is tied to the first part of the verse and therefore refers to the wings. Given this, there are still three interpretations:
1. The wings turned not when the wings went; The wings went every one straight forward.
2. The wings turned not when the creatures went; The wings went every one straight forward.
3. The wings turned not when the creatures went; The creatures went every one straight forward.
None of these three statements make much of a point, whether the creatures have helicopter wings, or bird-angel wings. Let us assume then that the first "they" refers to the creatures:
1. The creatures turned not when the creatures went; The creatures went every one straight forward.
2. The creatures turned not when the wings went; The wings went every one straight forward.
3. The creatures turned not when the wings went; The creatures went every one straight forward.