Do the enemies in OWB scale to the player's level. If so, what is the recommended level for OWB?

lowest lvl u should be is 15
and i think they scale to ur lvl

The weapons seem to scale I've noticed. Not sure about they're toughness/whatever else.

In the case of Robo-scorpions, they don't exactly scale but the higher your level is, the higher version of the robots you encounter.
As in, low level -> Robo-Scorpion Mk I
high level -> Robo-Scorpion Mk V