Getting compliments from stakeholders may be one of the factors that influences the panel to rank you higher, and it could contribute towards you getting a better performance grade.

But promotion is based on CEP leh.. raising CEP requires you to demonstrate the ability to perform some or all of the functions required at a higher level. Depending on what exactly the letter is about.. if it's about good T&L, probably won't help you get promoted faster. But if you get a lot of recognition (not just from parents but also colleagues/KPs/SLs) for strong Student Development work, you may be seen as a potential AYH and thus have your CEP raised.

Being awarded OYEA/PAT may be helpful. Or being a finalist.

Long story short.. faster promotion is very very hard to strategise towards. You just have to do your best, and wait for HR's magic finger. Nobody really knows how to game the system, and perhaps that was the design intent.