Hello tirthankar18,
It sounds as though you're having issues removing GoSearch9 from your Mac. We know how important it is to remove unwanted softwares. To clarify, when you're deleting GoSearch9 are you also emptying the trash after moving it there?
Also, have you verified that it's not an extension installed in Safari? You can view, and manage extensions using the steps outlined in the following article.
How to install Safari extensions on your Mac
If you've removed the extension, or it doesn't appear there can you let us know if GoSearch9 is taking place of Google or your preferred search engine? If so, you can verify your search engine settings by opening Safari, clicking Safari in the top menu bar where File, Edit, and View is shown, then click on Preferences in the drop down. In preferences click Search, then make sure the Search Engine is on the desired settings.
Have a great week.