Do I risk destroying the fan if I use a vacuum cleaner on my laptop?
You could damage the fan from spinning it that way. You could also damage many components in the PC using a vacuum cleaner - it generates a large amount of static electricity! You should NEVER use a vacuum on electronic equipment!
The proper thing to do would be to open the machine out and blow the dust free with non-static compressed air. (It's best to hold fans still rather than letting them spin freely for the same reason having the vacuum spin them up is bad, but very few people bother to do this because with quick bursts of air the odds are very slight.)
I have been told that each motor of the PC's fans relies on bushings, that are built to tolerate a certain RPM. Exceeding that RPM, such as when large volumes flow, can reduce the life of the fans. In addition, off-center suction can place a tangential torque on the axle of the fan. So you do risk this kind of damage as well.