Failing at creating a Network (EOS/IOS) playbook to validate STIG requirement

Question

Network guy pretending to "code"...(insert laughter/shame here). I am trying to create a playbook full of STIG requirements. I would like to be able to run this playbook against network devices, then easily copy the results into our the .ckl files.

In case it's not completely and utterly apparent, I have been using Ansible for less than a week.

*First I am having ansible register the output of a command. *Then I would like ansible to validate certain words or phrases are in the output of the register. *Then of course have a debug message state "Not a Finding {insert register here}", or "Open {insert register here}"

I cannot seem to get the "when {this pharse} (is (or not) in) register.stdout" to work.

Using Ansible 2.9

    - hosts: ios
  connection: network_cli
  gather_facts: no
  tasks:
    - name: Gather Username Configuration Lines
      ios_command:
        commands: show run | i username localadmin
      register: output
    - debug:
        msg:  "{{ output.stdout }}"
    - name: Username has correct privilege level
      block:
        - debug:
            msg: "{{ output.stdout }}"
      when: "'privilege 15' in output.stdout"

Output:

$ ansible-playbook ciscouserprivcheck.yml -u localadmin -k
SSH password: 

PLAY [ios] *************************************************************************************************************************************

TASK [Gather Username Configuration Lines] *****************************************************************************************************
ok: [Cisco1]

TASK [debug] ***********************************************************************************************************************************
ok: [Cisco1] => 
  msg:
  - username localadmin privilege 15 secret 5 $1$o1t2$VoZhNwm3bMfsTJ6e8RIdl1

TASK [debug] ***********************************************************************************************************************************
skipping: [Cisco1]

PLAY RECAP *************************************************************************************************************************************
Cisco1                     : ok=2    changed=0    unreachable=0    failed=0    skipped=1    rescued=0    ignored=0