In network language, "9 1" is used to express surprise, shock or admiration for something. This usage comes from the number "9 1", which sounds very similar to the Chinese word "wow" and is extended to express strong feelings. When people see something that surprises, shocks or admires them online, they will use "9 1" to express their feelings. This usage is very common in network communication, especially when expressing something novel, amazing or impressive.