It is not possible to run multiple queries in the one request. This is not supported by Athena as of now.
An alternative is to create the tables in a specific database. Dropping the database will then delete all the tables.
CREATE DATABASE db1;
CREATE EXTERNAL TABLE table1 ...;
CREATE EXTERNAL TABLE table2 ...;
DROP DATABASE db1 CASCADE;
The DROP DATABASE command will delete the table1 and table2 tables. This is not the preffered method as it may delete the tables you dont want to delete.
Hope this helps you.