[HandsomeRyan]

If I have a wheel with a Shimano 9 speed cassette, Can I use SRAM parts as long as the shifter and derailleur match each other (AKA: are both SRAM 1:1 ratio)?

Basically I have a Shimano XT cassette, I'm hoping to use a SRAM X.4 Derailleur and an X.5 shifter.

Will this work?

[Industry_Hack]

Yes, you can interchange cassettes. They even do that in OEM applications.