You can give it a go, it should boot, when I went from 09 to the test 10, I backed up my current setup, wiped everything boot, system, data, cache, then installed the build 10 test zip, followed by google apps and my kernel, did a wipe of data/cache, then rebooted back into recovery, restored only data and wiped cache and davlik cache one more time, then rebooted, it seemed to take some extra time but it did boot, however you want to do is your choice, but that's how I did it, and from there I flashed the final Build 10 this morning, and it all worked fine, but either way I like to wipe with each one, so I plan on doing that overnight, just so I don't have to wait for it to sync and re download all my apps again right now...
SO It SHOULD work, but if it doesn't or you have issues later on, then you will want to wipe, and once we get out of the BETA stage, there will be a good solution for not wiping with each new build..
May I presume no wipe from 9?