Is there a way for BIND 9 to automatically dump it's cache to a file before terminating and reloading it upon starting
+1 for a good question, but I must disappoint. While it's entire feasible to write the dump command into your shutdown scripts and a corresponding load command into your startup scripts, there's no "load cache from file" command.
It could be reasonably implemented, particularly if one were to decrement the cache timers based on how long ago the cache file was written. Presently (and I don't see this being accepted into the codebase), it's just not there.