My handy, dandy pocket reference states that a #9 drill bit has adiameter of 4.9784mm and a #8 drill bit has a diameter of 5.0546mm. Take your pick!
Linda in warm and sunny MA
Hello Catherine, You can probably find a drill bit the size you wantin a hardware store, but be very careful. A bit that size will easilygrab the piece you are drilling. This is dangerous. I might suggest atapered bur instead.
Have fun. Tom Arnold