Indeed, this works for me as well.
I've just migrated the arenas, bloom and isect to another machine with
a p9p tree from mid February and I had no problem unvacing my data
there. And for what it's worth, checkindex on that machine didn't report
any problem while it did on the machine with the recent p9p install
(which gives me the same vac/unvac issues as the ones already reported
by a few people).
So the data seems to be ok, which is already quite a relief.

Cheers,
Mathieu