The changes from 0.9 is mainly that the extension now supports the (currently) latest rubocop (0.74).
rubocop has often breaking changes so previously rubocop-sketchup has been locked to only with a single rubocop version. But rubocop-sketchup has been tested to work with rubocop 0.69-0.74. Hopefully that will lead to less update friction.
Notable change with rubocop 0.69 is that it dropped compatibility for Ruby 2.2. (Like many other gems these days.) So you’ll need to have at least Ruby 2.3 or newer installed on your system.