Yes, with a service provider that offers E911. There's nothing special required in the OBi, other than sending the 911 call to SP1 or SP2 instead of the LINE Port. It's an easy change:
Original:
Physical Interfaces -> PHONE Port -> OutboundCallRoute:
{([1-9]x?*(Mpli)):pp},{(<#:>|911):li},{**0:aa},{***:aa2},{(<**1:>(Msp1)):sp1},
{(<**2:>(Msp2)):sp2},{(<**8:>(Mli)):li},{(<**9:>(Mpp)):pp},{(Mpli):pli}
New:
Physical Interfaces -> PHONE Port -> OutboundCallRoute:
{([1-9]x?*(Mpli)):pp},{(<#:>):li},{911:spx},{**0:aa},{***:aa2},{(<**1:>(Msp1)):sp1},
{(<**2:>(Msp2)):sp2},{(<**8:>(Mli)):li},{(<**9:>(Mpp)):pp},{(Mpli):pli}
where spx is sp1 or sp2.