Hope you won't throw tomatoes at me, pinksoil, but the message seemed OK to me. You told him you didn't need to talk to him, but just wanted to check in, and a voice mail from him would be fine. So he left you a brief voicemail. Maybe he thinks he did just what you were asking him to, that that was all you needed. I'm not sure I would have picked up that you wanted him to tell you he was still your T, that he was still there, etc. from your message:
"Told him that I needed to check in; to engage myself a bit. Joked about breaking the '10 PM boundary'-- said I knew it was the only way he'd get me to call. Asked him to leave me a voicemail tomorrow-- told him that I didn't want to talk to him; that would explain on Friday-- that a message would be good enough." It sounds to me like he indeed said those things by acknowledging you have an appointment with him tomorrow. You told him all you needed was a message and you got one. I think they just can't read our minds, well maybe in session somewhat, but not over voicemail without the visual cues. I think he was not trying to make you mad. But could be wrong. You know your T! I will be curious to hear from you what he says in your session tomorrow. Maybe we should start a pool.
Hang in there, pink.