In the last few months I have had 2 different broods of small egged octos hatch out in my home aquarium. Yes, their eyes are open and for that matter their chromataphores (color changing skin cells) are already working and the babies color change when disturbed or agitated. If you check the "raising octos from eggs" sub- forum in the octo care section, you will see that I have posted a still pic and a small amount of video under "Aku's eggs." The photos were taken on by small stage microscope. I'm not sure how they push out of the eggs, the mom holed them up in a den out of site.
There are also large egged babies, which take longer to brood and don't have to swim around for a while, like the paralarval stage in small egged. Large egged babies hatch out like really tiny adults (but still bigger than small egged, which are about the size of a grain of rice), and begin life as benthic animals.
Again, if you look at that sub-forum, you will find links to large egged baby and my small egged baby experiences, where we try to post all the observations and pictures we can possibly get!