Prerana Waldorf School in Gachibowli and CBSE in the early years. How do reading and writing work?

Our son started grade 1 this June, in an IB programme we are broadly happy with. A friend's son goes to Prerana Waldorf School, and the two boys are the same age. Her son is cheerful, spends a lot of time outdoors, and seems to be at a different place with reading and writing than ours. I understand Waldorf schools have their own view on when formal reading should begin, and Prerana is also affiliated to CBSE. I'm curious how the two fit together in the early classes. For current parents: when do children start reading and writing properly there, and how did it go for your child when the CBSE expectations came in later?