No. 9 Group RAF (9 Gp) was a group of the Royal Air Force, which existed over two separate periods, initially at the end of the First World War, and latterly during the Second World War when its role was air defence.
History
The group was first formed on 1 April 1918 in No. 2 Area. The next month it was transferred to South-Western Area and then disbanded on 15 May 1919.
9 Group also supplied the staff that were trained by Robert Watson-Watt, the inventor of radar, to operate the Chain Home early warning system. The staff being RAF females (they were never WAAF members).
Falconer, J (2012). RAF Airfields of World War 2. UK: Ian Allan Publishing. ISBN978-1-85780-349-5.
Halley, James J. (1988). The Squadrons of the Royal Air Force & Commonwealth, 1918โ1988. Tonbridge, Kent, UK: Air-Britain (Historians) Ltd. ISBN0-85130-164-9.
Smith, David J., Action Stations 3: Wales and the North-West., Cambridge, UK: Patrick Stephens Ltd, 1981. ISBN0-85059-485-5.