If he is there 2 days a week, and they are assessing his readiness for school, how did they miss that?

I do worry about kids who stay back getting in to trouble bc they are bored and find things to amuse themselves. My dd is born at start of year and we are waiting awhile to decide on next year.
We had an info evening last night, school does not require any knowledge of letters and numbers (maybe recognising own name), mainly what they need is social and emotional maturity and an interest in learning. So I can see how they can 'miss' that knowledge because they are not looking for it, it isn't considered one of the 'readiness' things, whereas what they have mentioned would be.

I think is too early to make a decision but I would place some weight on what they say especially later in the year - particularly as school is more like the daycare/kinder environment than the home environment.

I think the opposite is also true - if daycare/kinder think your child is ready for school I would also tend to go with their view. I personally think it can be quite disadvantageous to life skills to be too far ahead and possibly bored.