Spread through food or water supplies is probably possible, given that CRISPR is currently mostly administered via virusses like AAV or lentivirus. But that nothing new, those virus cassets existed before, and can also be used with other methods like zink-finger nucleases or TALENs.
Delayed? I don't know, probably. It really depends on what you want to do. Keep in mind that most current applications affect around 0.5 percent of all hit cells. The effectivness of the process heavily depends on the construct and probably decreases with complexity. But sure, delayed promotors and other regulatory circuits should be possible, though unlikely for now.
The whole technology is dangerous, so dangerous that we probably cannot stop it now and have to form and regulate it. But it also has enourmous benefits associated, and again, can probably defend against itself. You cannot win evolution, only participate.
Whether this is playing god I do not dare to say (Last member of my family was babtised 80 years ago). When people invented the airplane people said that the sky is god place and they should not go there. Craig Venter was dubbed God 2.0 many years ago. Still, its just another new technology. In the 1940/50s antibiotics were a huge improvement, today its just what we are used to. I think I will get along with it, what you think depends on you.
But you can find genes that determine phenotypes that people think are racially relevant (skin color, hair texture, eye shape, etc) and you could imagine a gene drive that could do bad things to people with those genes. Whether those people are always (or even primarily) identified as or identify with a particular race could only be awfully approximate, but the effects could still be really bad.