ID doesn't say a god, as defined by earth's religions, is responsible for the existence of life on this planet. It simply says that an intelligence was behind life being on this planet. That could be ET's uncles and cousins for all we know. The point is that the complexity of life on the earth and the amount of time allowed (roughly 5 billion) years contradict a theory of gradual change and development.
Perhaps there's another planet out there someplace where "life" originated and this life is the source of other life in the universe. Perhaps, if we were on that planet a naturalistic explanation for the origin of life would be much more obvious than it is here on earth.
The point is this. Intelligent design doesn't necessarily mean a god. Like in the second or third "Star Trek" movie, it could be some kind of "genesis project" carried on by extra-terrestrial, intelligent beings.
Did the intelligent beings evolve naturally? If they did, why can't we have done so? If they didn't, who created them, and how did those folks come to be? Did they evolve naturally? And so on, ad infinitum.
You may believe that, and the proponents may be pushing that, but as I've been following creationism for a while, I've seen it evolve into Intelligent Design as a relatively more scientifically palatable way of saying "God did it."
To accept ID as purely scientific, I'd like to see evidence for it. NOT supposed lack of evidence for evolution not explaining things, but actual evidence showing ID. You advance a scientific theory by showing actual evidence for the theory, not by showing weaknesses of opposing theories. At most, that tactic can destroy the opposing theories, but will do nothing to advance yours (unless you believe ID would only accepted if there were a vacuum of theory on the subject)
At that, according to the definitions of hypothesis, theory and law, I'd say Intelligent Design is still far back at the level of hypothesis, untested and unsupported scientifically on its own.
Get some evidence and develop a real scientific theory, then you can try for equal time in the classroom.