Hey Gunjan,
You have lots of buses running from Delhi (ISBT) to Kedarnath (Sonprayag) daily operated by Uttrakhand Transportation Corporation.
From Sonpryag you will have to share a jeep till Gaurikund.
Then trek to Kedarnath Temple which is 16kms.
September is a monsoon season so its uncertain.
Its better to visit Kedarnath in the early monsoon.
Kedarnath remains open till October only.
Hope this answers your query.