Alcohol is no problem, shake out the excess if any is trapped under the heat spreader. Even 70% alcohol (30% water) is not likely to be do any harm after shaking out the excess if you install it in the board before it is fully dry, the surface tension is too low for it to bead up, it won't significantly conduct electricity.
The bigger issue could be that if the alcohol dissolved heatsink compound or other environmental residue, it could have deposited some of that on other underside of the CPU, fouling the contacts a little bit. Therefore you should inspect the bottom for traces of residue and if any are present, rinse the contacts with alcohol a couple times to clean them off.
I would not advise trying to dry the CPU with compressed air, because high velocity air causing fast dust movement will generate static charges. They are not likely to be of a magnitude that they do any harm, but since there is no need to 100% rapid-dry a CPU after spilling alcohol on it, there is no need for even a slight risk.