Do you know how long he is. I think for the larger species it's not able to tell their sex... Reliably until 5-7 inches. I know with smaller species it more around 4-5 inches
Can you a picture of his entire stomach area? Also some side pictures of that specific area would be good. If you do side pictures hold him up a smidge so there is air underneath him. It should help with telling if he has concave showing yet in his shell. But sexing at his age is still a bit hard. Leopard torts are one of the harder species to sex until males have a longer tail and from what I understand that can take a year or two.