Yes @Ali that's possible. You just have to add these two flags to your kops create cluster command.
--master-count int32               Set the number of masters.  Defaults to one master per master-zone
--master-zones strings             Zones in which to run masters (must be an odd number)
In your case:
--master-count 9
--master-zones us-east-1d,us-east-1b,us-east-1c