i currently have 5 male and 1 female, and they are probably the most docile fish in my tank other than cory's. ive never had a problem with them in any tanks. i didnt want the female i got, but it was easier to leave it in teh bag than get the guy to try catch another male.
I was told that the ratio of males to females should be atleast 3 females to 1 male but that is to stop them pestering the same female, stressing them out. I never thought about males only, I assume they will be ok.
i always found to get the best colours out of Cherrys is a mix of 2 males / 3 females and although the females are not so bright, the contrast against the males, and like what has been said one of the most peaceful barbs around...
They are very peaceful fish, though i don't know what keeping 8 males together would be like (they do prefer the company of females and you will propably see them acting more naturally if you keep them in a good gender ratio- the chances of them successfully having fry in a community tank is minimal). They do best by far being kept in planted tanks though (doesn't matter if plants are real or fake though real is better) in chilled out communities.