H1B amendment on a promotion Needed?

Hi, I need some help, (I am in H1b -I140 approved)

I got promoted and my job title changed from Senior Tech lead to Technical manager. My role became Technical Architect to Senior technical architect. My salary increased by about 9%.
But my work responsibilities truly remained same with same client same location,

Would it need a H1b amendment, LCA update?
If yes , in what time frame should i do this? what if i have a extension in 1 year time?
What if my employer doesnot do this properly?

It is hard to say just based on this. You need to ask your employer, they will review the SOC Code and the Job Description for what you were hired and filed H1B. If they see any changes, then they should file for the same. Just salary hike does not mean you need new H1B, talk to your attorney and employer on this.
Well, if you think they are not doing it properly, you need to suggest that it is wrong and get it corrected. It is your career. talk to another attorney and get it clarified, if in doubt.