You simply need an open-collector driver, with the collector having a pull-up resistor to the 9V supply - please note though, this inverts the logic - but is easily cured in the software.
Many PIC's have a single open-collector output pin (usually RA4), but I don't think the 12F675 does?.
Are you sure the transmitter requires a 9V input signal?, it might work quite happily with a 5V signal - you could try it and see.