You did the best thing for him by allowing him another year to grow. It's important to understand that a child's brain is most open to learning reading concepts around ages 6 and 7, yet as a society we label kids that aren't reading by the end of kindergarten as "slow learners". There is something rather hypocritical about that.
That being said, your son sounds like he is expressing all the great things that he has learned through play. I think that if you want him to do more academic type things than you need to introduce them to him. You can do this through play with things like sand--write the letter large in black ink on a piece of white paper and cover it with sand, have him trace the letter through the sand. You can have him cover letters with pasta or buttons or other types of small objects. Play board games with him to work on numbers and social skills. And of course, read together and often.
Mama, always keep in mind that we expect our children to do so much at such a young age nowadays. I'd combine his play learning with a bit of directed learning and see how it goes. If your goal is to have him taught in a teacher directed setting than sitting with him and working on academic type skills will only serve to help him become ready for Kindergarten when his time comes.
Good luck, with a lot of love and patience he will continue to grow.
