Sshfs uses ssh to start a file server program (generally called sftp) on the remote server.
Under sshv2 this is described as an external subsystem, i.e. a specific message is sent to the server to start the file server subsystem. Under sshv1 which is what the plan9 ssh server supports, the client needs to envoke sftp binary directly. I believe the sftp binary from the openssh port should "just work" if the fuse sshfs port is capable of working with sshv1 and being told the command to send. sftp in this context is unrelated to the port 115 simple file transfer protocol (sadly also known as SFTP) nor to the traditional port 21 ftp server. an sftp client for plan9 has been on my todo list for... years. -Steve
