OTS02, sorry for the delay, it's been a hectic week.
I just ran the virtual server code against my 9.6 box and it's working fine, although I didn't do it with the pool interface. There should be values returned if you specify the correct persistence mode in the request and you actually have persistent connections of that type at the time of the request. If this method is not returning values for you then you'll likely need to get in touch with product support as it looks like it's a problem with the server code.
-Joe