Installing RH9 the easiest way (apart from automatically partition) is using Disk Druid.
If you give it a go you'll be fine for the future. To get you up and running just create 3 partitions.
Create the first partition and call it /boot make it type ext3 and make it 100MB,
Create the 2nd partition and call it / make it type ext3 and make it say 10GB if you can,
Create the 3rd partition and make it type 'swap' you should normally make this partition twice the size of the amount of RAM you have in your machine.
If you do that you should be right to install the rest of RH9, and it WON'T remove your XP partition