Humanitarian unitarians don't think that the NT actually does ascribe creation to Jesus, and subordinationists think those texts make him the instrument of God's (the Father's) creation - God being the creator in an ultimate sense, and the pre-human Jesus in an instrumental sense. Both would agree on the uniqueness of the Father, and of course both with agree with trinitarians that Jesus is the visible image of the invisible God. Again, both agree that the Father, YHWH, is god in a sense which not other being ever has or will be, and that he knows all. Again, in an ultimate sense, salvation is from the Father, but of course it is through the Son. So no, as far as I can see, unitarians don't have any obvious problem with Isaiah.
Unfortunately, Dale Tuggy is using a redacted Bible. Malacoda, executive secretary to the Dark Lord, sent me a copy of the original Bible, via InfernEx. The courier, who bore a startling resemblance to Hellboy, had me sign for it.
As it turns out, the Urtext of Scripture doesn’t actually ascribe creation to Yahweh. Before he fell, Yahweh was merely the instrument of the Dark Lord’s creation, Lucifer being the Creator in the ultimate sense.
But after he fell, Yahweh redacted the Bible, editing Gen 1 to omit the Dark Lord. In our redacted MSS of Scripture, Gen 1:1 is really 1:2. Our copies are missing the original first verse, which reads: “Before the beginning, Lucifer directed his servant Yahweh to make the heaven and the earth.”
Again, in an ultimate sense, salvation is from the Dark Lord, but of course it is through Yahweh. So no, as far as I can see, Satanists don’t have any obvious problem with Isaiah.