There would be a difference between the name of a SAS dataset (such as you would use in a SET statement) and the name of a database location or table (such as you might use in a LIBNAME statement) or the name of an operating system file (such as you might use in a FILENAME or INFILE statement). However, in any of these cases, after you read your Excel file, then you could create a SAS macro variable from your variable value using either CALL SYMPUT or a PROC SQL SELECT with INTO. Then, the macro variable reference could be used in a LIBNAME statement or a SET statement or in any other code where you needed to reference a value that had to come from a variable value in a different data set.
If you don't know about SAS macro variables and how they work, this paper has a good introduction to SAS Macro concepts. http://www2.sas.com/proceedings/sugi28/056-28.pdf
(Step 4 shows the CALL SYMPUT method of creating a macro variable; Step 8 shows the PROC SQL method.)