Can't do it in v9
In v9 and prior, the volume to be restored from must exist in the catalog when the restore job is created. v10 has a tmaplat that will let you do it, tho.
I suppose that if you wanted to spend the time, you could script up someting to determine the latest volume and then submit a job using that volume using BEMCMD, but it would probably be quite a bit of work.