I am no expert, but what I would do is make it a really cosy den for him. Snuggly bed, and cover over the top so he can't see out, but there is ventilation for him. Put his favourite toys in there and yummy treats, you could also try feeding him his dinner in there, he needs to feel that this is a safe, secure and comfy place to be. I always used to give mine a chew that took a few minutes to eat, then shut the door covered them up and just left them to it. You could try leaving a radio on or tv, so he maybe doesn't realise he is alone.
My girls are 12 months old next week and still sleep in their crate with the door shut, they howl if I leave it open.
It is their safe place, so I would persevere for a little longer and if he really doesn't take to it, then maybe ditch it, but you really do need to give it time, they don't all accept them straight away. Little and often is the key, put him in cover him up and leave him, if just for a few minutes then go back and let him out, but only when he is quiet. Gradually build up the amount of time you leave him, once he realises you will go back to him eventually you should be oK.