recce_FAC,
You are misinformed. 'They' are not getting rid of the GR9. The RAF is losing one squadron, leaving the remaining three to see the type through until it is replaced by the F-35 Lightning.
There is less than one whole RAF squadron deployed to Afghanistan for the CAS/recce role, as the RAF has 7 squadrons of Tornado GR4's as well as the Harriers, as well as the Typhoon force, the GR9 is being rested after a pretty grueling non stop deployment to Afghanistan.
You may have noticed that there has been just a teensy weensy world wide recession, so the defence budget is under pressure, along with the rest of UK public expenditure, and will face reductions in the next few years.
The one Harrier squadron going early is a part of that reduction.