Inserting dial 9 in front of a Zul originated call

Can a dial 9 be automatically inserted in front of a number when click to dial on FireFox or Chrome?

No Zulu can’t prepend numbers automatically but why don’t you just don’t at your outbound route level at the PBX.

You could always submit a feature request to maybe have it added to the browser extensions.
https://issues.freepbx.org/secure/Dashboard.jspa