Not to mention the fact that the Psalmist could easily have referred to them as angels or demons or spirits.
There are reasons for that, some of which I have already listed:
a) an angel is a messenger from God. It wouldn't have made any sense to list them as messengers.
b) the OT doesn't really have a worked-out demonology, and given how demons are described in the NT (and they are never described as fallen angels), then that wouldn't work here.
c) The text lists them as elohim and beney elim, and the passage parallels the beney ha-elohim in Ps. 89. That's the clinching argument right there.