Those octopuses labelled "joubini" are usually the dwarf "mercatoris". We have several people keeping mercatoris - search for mercatoris to find them all. Einey (Einstein), Animal Mother's octopus, was a mercatoris. Lev has a thread about his efforts at raising mercatoris babies.
I have kept quite a few O. mercatoris and reared several clutches. Frankly, as aquarium species, they are pretty dull. They remain tightly holed up during the day and only come out at night. They are shy and not interactive. And you will have an adult for only a few weeks. However, rearing the hatchlings is interesting and doable.