The rear hangars were far more open in the early days. Here is a pic from, I would think, late 40s so they presumably were used for aircraft.
LTNman is right in that hangar 24 is not directly behind hangar 9 but the next one along.
When I first started cycling to the airport c1960 the front of hangar 9 was used by Percivals for their flight line aircraft and the rear by Luton Flying Club until they moved to the hangar vacated by McAlpines when they moved to the east end of the apron (a former Blackbushe hangar I was told). Clear?