ATX RWY INCURSION HAD LTSS FROM ACFT TKOF. SYS ERROR.

Narrative

EARLY IN THE MORNING; MYSELF; A FO AND AN OBSERVER PLT LEFT THE W RAMP AT YIP. OUR CLRNC WAS TAXI TO RWY 23R VIA N ON THE RAMP AND RWY 9L. THIS WAS ONE OF THE 2 STANDARD RTES USED TO GET TO RWY 23R. THE CLRNC WAS READ BACK BY THE FO AND WE TAXIED WITH ME AT THE NOSEWHEEL TILLER AND BRAKES. WHEN EXITING THE RAMP ONTO RWY 9L; I AND THE OBSERVER PLT NOTICED A TAXI/LNDG LIGHT AT THE OTHER END OF THIS RWY. ATIS SAID RWY 23R/L WERE THE RWYS IN USE. REGARDLESS; IT IS COMMON PRACTICE AT WILLOW RUN TO USE ALL RWYS TO EXPEDITE THE FLOW OF TFC. I WAS AWARE OF THIS; YET CONTINUED ON RWY 9L ASSUMING THE TFC WAS AWAITING IFR RELEASE FOR RWY 23L OR R. WE CHKED IN WITH TWR FREQ APPROX 1/3 DOWN RWY 9L. THE CTLR IMMEDIATELY TRIED TO CANCEL THE ACFT'S (BEECH BONANZA; OR BARON; I BELIEVE) TKOF CLRNC. THE ACFT WAS ALREADY AIRBORNE AND PASSED WELL ABOVE US; 200 FT OR MORE. AFTER OUR DEP ON RWY 23R; I ASKED THE CTLR IF WE HAD MISUNDERSTOOD THE TAXI INSTRUCTIONS. HE SAID NO AND APOLOGIZED SINCERELY. SUGGESTIONS: ANTI-COLLISION STROBES ON WHEN TAXIING ON ANY RWY; CHK IN WITH TWR WHEN APCHING YOUR RWY BUT TAXIING ON ANOTHER RWY; ADVISE IN THE ATIS ALL OF THE RWYS THAT MAY BE IN USE; HAVE ACFT FROM THE E RAMP AWAITING IFR RELEASE FOR RWYS 23R/L HOLD SHORT OF RWY 27R.