upgrading to 9.2 (IMac)

[Jack Honeycutt]

I am helping my friend upgrade her IMac.  She is currently running 
8.6.  She has bought 9.1 and I think she also has a 9.2 upgrade CD.

She asked me to upgrade her computer for her (she is new to computers).

Can I go directly from her 8.6 OS and upgrade to her with her 9.1 CD?  And 
after that, will her IMac then take the 9.2 upgrade CD?

What is the minimum amount of RAM that she needs for her IMac to run 9.2?

Thanks in advance.

Jack in Portland Oregon