I have run across a bound copy of the Civil War diary of William Henderson of Co. D, 9th Batt O.V.I - THANKS to Anthony Powell for confirming Henderson's assignment.

It is currently listed on eBay if anyone is interested-
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=7302558463&ssPageName=STRK:MESE:IT