"this "bow" is a NEW THING."
I don't think that is certain.
The verb is translated make as I thought. It is nathan not bara. It also says it is a "token" or "symbol" of the covenant.
I don't think there is much to the rainbow being created as a new thing in this verse (Gen 9:11)
Gen9:
13-I *do* set my bow in the cloud, and it *shall* be for a token of a covenant between me and the earth.
14-And it *shall* come to pass, when I bring a cloud over the earth, that the bow *shall* be seen in the cloud.
present and future tenses. no indicators of past presence of the rainbow or a rededication of an extant phenomenon. all indicators point to a new thing.