Can a dimmer switch be on the same circuit with outlets?
Yes. As all devices are connected in parallel there's no relationship between the switch and the outlets. In fact, You'd be lucky to find a dimmer switch that isn't on the same circuit as some outlets. It's quite common.
You're correct that it's not legal or safe to use the dimmer to control the outlets, though. That can lead to low-voltage/high-current conditions and device failure or fire.