It is a very tough job to delete 9gag comments from a very active thread as your comment will be hidden somewhere amongst thousands of comments. But I will share with you an easy way to do it. Using this method you will be able to go to your comments directly one by one and delete them no need to search for needles in a haystack. Let us dive into the process step by step.
Request your data from 9gag
The first step is to request your data from 9gag. You can do this by going to Profile->setting->privacy and safety. See the image below
Once you click on privacy and safety you will get an option to request data
Once you click on the Request my data button, 9gag will send you all your data in an HTML file after some time maybe one or two days.
Deleting 9gag comments
Once you get your 9gag data in an HTML file in your registered email then you need to extract it and open it in a browser. It will be something like this
Now, this HTML file has all your 9gag data. To delete your 9gag comments scroll down till you reach the comments section. The comment section will have the time of the comment and a URL directly linking to your comment, yes directly linking to comment no more searching. See the image below
The left block consists of a time of creation and right block will have direct links to comment. Now from here, we need to go one by one through each link open it in 9gag just by clicking and deleting the comment if you wish. As of now, it is a manual process from here on if any of you fellow 9gagers come across automation do let me know in the comments. Hope it helps