I have some queries regarding extracurricular activities :-Is

1)Is extracurricular activity very essential for IIM interviews ?Do we always need to have certificates ?And should extra curriculars be always those after class 12 ?I heard extra curricular at school level are not considered ...I have learnt classical music for 6 years but I dont have a certificate ..Can I mention it ?

2)Is it a problem if I have done an online course e.g. web development from www.w3schools.org and have got a certificate ?
Will website development be considered as an extra curricular ?

3)Currently I am learning Rabindra Sangeet from a place ..but I dont have certificate ...will a proof that I am their student be enough or will I need a certificate ?