I have 2 girls who are not sooky at all, they are outgoing, have been at CC from 12m and generally always happy to go with people they know other than mum and dad - no issues.

BUT both of them had exactly what you are describing in terms of separation anxiety at age 3. It was only with me, not with their dad and was so bad at times that he had to do all of the drop offs because it was just too traumatic. With DD1 I assumed it was because I had DD2 at home and wasn't working and that she knew so she was putting on a show but the CC carers told me that they see it a lot at that age and they assured me it was a developmental phase. They told me this again with DD2 but because I had seen it before I wasn't worried.

There is a lot of time to mature between now and starting kinder next year so I would go with your gut and what you believe. I would also flag it with the teacher next year to keep an eye on him and if there are still issues he can repeat 4 yo kinder (assuming that because I am Vic and you can do that).

Don't beat yourself up, you know him best, go with what you believe to be the best option for him.