As Cai said, working in picas can be very confusing, especially since almost everyone I've dealt with gives measurements in inches or millimeters.
According to Wikipedia:
The pica contains 12 point units of measure (.1660 inch)
So you can see where the math gets to be a pain.
Go into your preferences and change your measurements to inches (or mm), as pictured below
Now, for setting up the document. There will be a tiny bit of math involved, but it's easy.
I'll break the terms down for you:
Trim - This is the final dimension of the document, after it has been printed and then cut down to size.
Bleed - This is the Trim size, plus the parts that will be cut off after printing. This is done because printers typically can't print to the very edge of the material, so they print a little larger than the desired size. This allows any designs to be carried past the edge, then trimmed to final size.
Live Area - This is the area in which you want to keep all of your critical design components, such as images/graphics (not counting background designs), text, etc.
9.25 - 9 = .25" You then divide this by two, since the bleed will be applied to both sides. This gives you a bleed of .125"
Repeat this process for the rest of the measurements, keeping in mind that the measurements need to be divided and applied to both sides.
Set your document up as follows:
The red line on the outside of the document is the Bleed. The magenta line inside is your Margin (live area). The white area is your final document's size (Trim).
Once you do this enough, you will begin to see patterns and common sizes, so it gets easier. Decimals/fractions can be tricky at first, but once you realize that they are typically in 1/8" (.125") increments (here in the US anyway) the math gets much easier to recognize.