what is the main difference between V9 ,V10 and V11 in both GTM and LTM ?

Are you asking for advantages of BigIP v11 when compared to older versions (BigIP v9, v10)?

You can check the product release notes for the best answer.

To summarize, BigIP v9 is obsolete (too many vulnerabilities), BigIP v10 is obsolete but still somewhat tolerable (you can still get a decent level of security with iRules and latest hotfixes), BigIP v11.5.4 is the current long-term stable release and industry standard.

Even if you don't need any of the new features, you will need to upgrade to v11 for security reasons.