It's absolutely (almost) correct! HTTP/0.9 does not require you to send back a status code or any headers. Some modern web servers even recognise a lone "GET /" to mean HTTP/0.9 and will respond accordingly.
This is exactly my point - it successfully accomplishes a very specific task, in a way that is fragile and context dependent, and completely fails to handle any errors or edge cases, or reckon with any complexity at all.