Use of Irq 9?

Ihave some problems with deciding which irq to use for my ethernet card. Possibilities given as a choice include 3,5,9,10,11,12 and 15. At the moment, before installing the ethernet card, 3 is taken by a serial port, 5 by usb-uhci, 9 is not mentioned on this place but somewhere it says it is a bridge, 10 is my soundcard, 11 is my TV card and 15 is ide1. My question is, could I put the ethernet card on irq 9? Or should I put my serial port which is used for an UPS on another irq? In that case, which one?