> 1. With v7 each directory that had a subdirectory had a + sign in the location window. Now with v9 only the directory I happen to be sitting in shows the + sign.
You're probalby viewing a network drive. Network folders (eg on a NAS drive) don't show whether they are expandable because pre-reading the whole tree might take ages.
> To navigate to a different subdirectory elsewhere on the drive I have to first select the parent directory, kill TP9, and restart it.
That's just weird. But instead of restarting TP9, try pressing Ctrl-F5 (refresh tree) if this happens again.
> 2. Each parent directory has in it all thumbnails for all subdirectories under it. This causes TP9 to take forever to start. Clearly I do not want this, I want the thumbnails to only be displayed in the directory or subdirectory I choose.
Well, you shouldn't have turned that option on then :-)
To turn it back off, Go to Options | Preferences | Thumbnail View and unmark "always show child folders".
If you prefer version 7, you can simply re-install it (in a different folder than v9). There's no need to remove either version if you also want to use the other.