Mmh. I did that in three instances and in all three it worked. I think just reinstalling should be all you need to do.
... Not sure whether 1.09 is an inclusive package, but 1.08 is still available, so just apply 1.08 first and 1.09 second, to be on the safe side.
Your saved games reside in <installation path>/scenarios/save games/ - carry them over as you see fit.
If you wish to inquire about error messages, please do show (or cite) - the error messages.
Completely, not somehow embellished and/or abbreviated.