I'm looking for software that is capable of scanning a barcode from a document (maybe by only scanning a certain section?), searching an XLS file for that scanned number, and then exporting the corresponding data from the same row in that XLS file into a CSV file, comprised of all the data taken from the XLS.
This is either a (mostly) off the shelf Point of Sale system, similar to what you'd see in a checkout line, or
A full custom coding job. Depending on the rest of your unknown requirements, it could be done relatively easily, even in Excel.
But don't get hung up on 'it has to interface with an XLS'. The right solution may be something else entirely.
When laying down software requirements, generally it is better to start off in very general terms, rather than specifying particular file formats.
What is the workflow?
"I need to scan in a barcode, search for its corresponding info in the database, and output that info, possibly to a CSV file."
How many users, how often, number of locations, budget, timeline...all have an impact on the final solution.