When you select the Edit In Photoshop option in Lightroom CC 2015.10/Lightroom 6.10, you receive the following compatibility warning despite having Camera Raw 9.10 installed:
This version of Lightroom may require the Photoshop Camera Raw plug-in version 9.10 for full compatibility.
Lightroom CC 2015.10/Lightroom 6.10
This is an erroneous warning in Lightroom CC 2015.10/6.10. As a workaround, select Open Anyway to edit your image with full compatibility.
This issue has been fixed in Lightroom CC 2015.10.1/6.10.1 release. To avoid getting this erroneous message, update Lightroom to the latest version. For details, see Keep Lightroom up to date.