I got below Error:
function get_course_category_tree is removed, Please use course renderer Or coursecat class
When I didn't found compatible function.
I would like to hear solution for this issue
Look in the M2.9 code for the method's depreciation notice and that will tell you what to do.
This is most probably related to the theme you are using. If you can tell me the name of the theme I can perhaps try and get a fix for it.
Here is a link to a question someone asked in 2013 when that 'function' you quoted was depreciated in the Custommenu and has been so since Moodle 2.5.