Bob you need to do some testing. I also really hate to power off my SS amps. But even unplugging your interconnects is probably unsafe, because while doing so, large transients can occur which may damage tweeters, etc.
You need a DVM (pocket voltmeter, or better yet an oscilloscope) or can you arrange for testing at a dealer's repair shop. Observe the preamp's outputs for transient voltages while powering it on & stabilizing. Again observe for transients while powering down. If you notice any significant voltage spikes during turn on / turn off then obviously you're stuck leaving it on. If only small signal spikes or none are observed then you're safe to turn the pre off & on with the PA left operating. I have a tube Cary pre, SLP98L which has standby mode & also powers on/off cleanly so I can get away with it. I've read here that 'standby mode' doesn't save your tubes, but what else would be it's purpose I don't know?
If the CJ has a mute switch (this Cary has that too) then it may be safe to toggle your power while in mute mode? "Mute" may even ground the pre's outputs; some are designed that way. Hope this helps.