Jon,
Philly starts to use the Converging ILS's when the ceiling gets at or below 800 feet or about 2 miles visibility. Jim kinda mixed it up, the Missed Approach for 17 turns left to PNE and up to 3000. And just as the word converging says 9R climbs up to 3000 and right to OOD. If you still don't understand why these procedures are in use. In IMC conditions, if two aircraft on each ILS would go Missed at the same time and the Converging ILS's are not in use. It would not be a good thing since 17 and 9R Missed/Go-arounds would intersect. And just to explain a little more, 9R and 17 are used in heavy IMC conditions because 9R is our only runway that is CATIII and with ALSF-2 lighting. 17 is used obviously because 35 doesnt have an ILS.