A little difficult to tell from the picture. It kind of looks like the camera focused on the anus and that the body parts relevant to the question are kind of blurry. I see the dark blob, but I can’t make out details like the shape of the opening.
How old is the kitten? Usually by 4 months (often sooner) the presence/absence of testicles will be fairly clear, although there are the occasional boys who are delayed on that.