No .... the space aliens are your idea.
The reason I say ID is "inherently plausible" is because we humans have an innate understanding of the concept of design -- we practice it all the time, and so it's not that hard to extend the idea to the origin or development of life. (And on the latter, it's all the more plausible because we've been using ID to influence the development of life for thousands of years.)
Whether or not ID is a true explanation of things, it is nevertheless true that we can think about how we would go about the process of creating life.
I'm guessing that with about 10 seconds of thought you, personally, could sketch out at a top level the steps needed to do it, and within a minute you'd probably be diving into one or another of the vexing questions (e.g., how would you store and retrieve information....?)
See what I'm getting at?
No. Space aliens are Behe's and other Intelligent Designers' idea.
The Designer in Intelligent Design is not God according to Behe, because Intelligent Design is not about religion. That only leaves unknown extra-terrestrial intelligences that were here before any life existed on the planet.
In Behe's own words from his "Molecular Machines":
There is an elephant in the roomful of scientists who are trying to explain the development of life. The elephant is labeled "intelligent design." To a person who does not feel obliged to restrict his search to unintelligent causes, the straightforward conclusion is that many biochemical systems were designed. They were designed not by the laws of nature, not by chance and necessity. Rather, they were planned. The designer knew what the systems would look like when they were completed; the designer took steps to bring the systems about. Life on earth at its most fundamental level, in its most critical components, is the product of intelligent activity.