Do We have any specific editor IDE for write or edit code in widgets?

Widget Studio is the IDE for editing widget code. The export XML is intended for transporting widget code from one Community to another or for archiving. While the components in the export XML can be edited directly, they would need to be separated to be easily editable in an external IDE and then reassembled to import back into Community.

Widget Studio is responding slowly once the user started editing the code. It immediately trying to save changes but that time Developer is blocked until it got saved. In the previous version 8, it was working much better. Auto save functionality is a drawback. 
Can we do any setting changes to stop this auto-save functionality?

The auto-save behavior cannot be disabled. That said, you do not need to wait for it to complete. It is saving in the background and is non-blocking.

No, It is blocking. I can create a video and share it if you want.

Which browser/version on which OS/version are you using?

Google Chrome Version 87.0.4280.66 
OS: Windows 10

I am testing on Windows 10 w/ Chrome 87 set to simulate "slow 3g" speed (just to ensure the saves take a long time). I am editing the content script of an existing widget.

• When I make changes, I see the "Changed" status show immediately above the editor.
• When I stop typing for a short period of time, I see the status change to "Saving...".
• While "Saving..." is shown, I continue typing. I am able to type and the status changes immediately to "Changed."
• When I next stop typing, the "Saving..." status reappears and, if I do not type anymore, it changes to "Saved."

Are you seeing different behavior? If so, could you provide reproduction steps?

Yes, only 3rd condition is not fulfilling in my case.

• When I make changes, I see the "Changed" status show immediately above the editor. - Correct
• When I stop typing for a short period of time, I see the status change to "Saving...". - Correct
• While "Saving..." is shown, I continue typing. I am able to type and the status changes immediately to "Changed." - Not Correct for me
• When I next stop typing, the "Saving..." status reappears and, if I do not type anymore, it changes to "Saved." - Correct

While Saving I continue to type then the text did not appear till the saving process complete. It seems like hang.

Yes, only 3rd condition is not fulfilling in my case.

• When I make changes, I see the "Changed" status show immediately above the editor. - Correct
• When I stop typing for a short period of time, I see the status change to "Saving...". - Correct
• While "Saving..." is shown, I continue typing. I am able to type and the status changes immediately to "Changed." - Not Correct for me
• When I next stop typing, the "Saving..." status reappears and, if I do not type anymore, it changes to "Saved." - Correct

While Saving I continue to type then the text did not appear till the saving process complete. It seems like hang.

Could you record of a video of that behavior and also identify the number of open tabs referencing the Community? If possible, could you have the Network tab of Chrome w/ Widget Studio open to show current traffic in the video?

Could you also provide the full version number for your community from Administration > About?

Sure, once I'll create and post it here.

Thanks. Sorry for the hassle of that. It may help diagnose the issue as what you're experiencing is not the intended behavior.

Below are the Community version details: