My 9 year old told me hes hearing voices?

a couple years ago my son said he kept hearing a voice all it did was count or say his name the dr asked him if he still heard it he said not anymore the other day he said he was hearing it again and it was telling him to do bad things such as throw things at his brother and sister and spit on them he also said it scares him it tells him to do things he doesn't want to do, if he does what it tells him the voice will stop it controls his dreams and makes him see things that are not really there. is he using this as an excuse to misbehave or does it sound like he could be telling the truth is there a way to tell for sure