Can you be woken up by a creeper in prerelease versions of Minecraft?
The 'wake up' mechanic was removed in Minecraft Release 1.0.
This answer is only relevant for versions of Minecraft built prior to that revision, accessible using the Minecraft Launcher's Time Machine functionality.
No, a creeper can not wake you up/be a nightmare.
The results would be catastrophic and are therefore disallowed just like a creeper mob spawner does not exist for the same reason.
bugi74 has done some great research on the code itself which verifies this:
On each try it will roll a random monster type from the subset of skeleton, spider or zombie
"Unsafe according to the game's rules but does not actually have an ordinary path to a dark area" seem mutually exclusive. If a hostile mob can get within 2 blocks of the bed (even through walls) there is the possibility of being woken up.
I have seen numerous posts on the minecraft forums referencing being woken up by a creeper/spider but bugi74's interpretation of the source code suggests that creepers cannot spawn.
Image from Minecraft Wiki