@jayakhan04-gmail , assuming that you are :
(a) Physically present in the USA
(b) valid work visa / EAD
(c) and have a TIN ( SSN )
(d) that you do not wish to assert treaty benefits
(e) and NOT filing a 1040-NR
You should use the W-9
Question in my mind is if you are on OPT, where do the RSUs come from -- an earlier employer in another country ( home country )?
Saalam Alequom
pk