Since Boracay's beach is pure fine sand - even in very shallow water kite surfing is safe. In other places like Maledives the reefs are huge and most beaches are protected by reefs making any surfing in waves potentially dangerous.
On Boracay all shallow waters that produce waves are always sandy and safe for landing or crashing. Free of sea urchins or sharp objects such as corals - you can stand anywhere safely.
The many km long beach stretch make Boracay white beach an ideal location for kite surfing beginners.