Multiplexer with 5v select and 9v or more routing
Analog devices make some parts that can switch larger signal ranges than the logic levels of their control signals. I'm using the ADG1404 for such an application in one of my current designs.




  When looking at the datasheet can you point out what tells you that a device is capable of that. Knowing what to look for would be really helpful when picking the components i need for this project.


In the case of the 1404 it's in the headline features


Fully specified at +12 V, ±15 V, and ±5 V 
No VL supply required 
3 V logic-compatible inputs


In my experiance at least with Analog Devices most of their parts with digital control inputs (switches, muxes, instrumentation amps, digipots etc) tend to have logic inputs with thresholds that make sense for modern logic even while the analog ranges are much wider. It is also common to have seperate ground and negative supply pins to allow the logic to be referenced to ground while the analog signals passing through are bipolar.

The 4000 series is extremely old so it's not so surprising that it doesn't have modern conviniances.