@DerekColley 

Thank you for sharing the link. It appears that the link you provided is for the UK version of the Deco P9. Below, I have included the link to the US version of the Deco P9 for your reference.

https://www.tp-link.com/us/deco-mesh-wifi/product-family/deco-p9/

Please note that firmware versions may vary by region, and it seems that static routing may not yet be available for the US model of the P9.

I recommend submitting a support ticket to request the addition of this feature for US users of the Deco P9. 

You can open a ticket by following the instructions below.

1. Email support at support.usa@tp-link.com.
2. Include the model number of your Deco router, as well as the hardware and firmware versions.
3. Describe the issues you are facing and send the email.
4. Within a few minutes, you will receive an automated response with a TKID number.
5. Upon receiving this email, please access the Deco web UI by entering "tplinkdeco.net" in your browser. Navigate to Advanced > System > System Log, select "ALL" in the log type, and save the file to your local computer. Then, reply to the email you just received, attach the log file, and kindly request that your ticket be escalated to a senior engineer for further assistance.

  @DerekColley 

Not sure what the email is for support in the UK but here is the support forums 

https://community.tp-link.com/en/home/forum/39

  @DerekColley 

Hi, Thank you very much for the feedback.

Deco P9 with the latest firmware 1.2.1 doesn't support the "Static Route" yet.

Best regards.