CrossRoads:
http://www.ti.com/lit/ds/symlink/cd74hc4051.pdfVee would be Gnd per TI's datasheet.
They call Vss ground, not Vee. We are talking about the CD4051, not the 74HC4051 though - there will
possibly be differences in thresholds.
I'm not sure you can reliably drive the control inputs from 5V when Vdd is 9V, it would be more common
for Vee = -5V, Vss=gnd=0V, Vdd=+5V from what I understand.