I agree that the fins and bodyshape look male to me, but I always advocate looking for ovaries to be completely sure. Since this betta is light-bodied, it should be easy enough to tell, just shine a flashlight at them from behind. If there's a big triangular shadow behind their stomach, they're a female and if there's not, they're male!
And yes probably a delta tail, their fins may grow into a full HM spread when they're mature but I would be surprised. Very cute either way! :)