Welcome to Android Central! If there's a Bluetooth switch in the system settings, then it should be available. The "Unfortunately Settings has stopped" error is more likely due to some problem with the firmware or other 3rd party apps causing instability. Does this persist after a reboot? Or in Safe Mode? On most Android devices, while powered on, press and hold Power until the Power Off menu appears. Press and hold the Power Off selection until the Safe Mode prompt appears. Tap OK.
EDIT: What's the exact model number of your tablet? I looked up a 9" Proscan tablet, and it does not have Bluetooth:
http://www.hhgregg.com/proscan-9-8g...blet-with-case-and-keyboard/item/PLT9650GK8GB. It's possible that yours doesn't have Bluetooth, but they didn't bother removing it from the settings menu. If the tablet didn't come with Bluetooth, then you'd have to look for a USB Bluetooth dongle that's compatible with the tablet. I doubt you'll find one, because these kinds of dongles are intended for PCs, not for Android devices.