We have found that the ksc_run_sql special command works when executed in a workflow step only if the workflow step has source and destination environments specified. The environments must be specified even when an ENV_NAME parameter is specified on the command like you have done here. Since no workflow step is associated with a report, this special command may not be functional in reports.
You can use ksc_local_exec to execute sqlplus directly. The [exec.output] token should be usable to capture the output but I have not tried that sequence in a report.