Inside the Kodaikanal you cant get the bus only to reach the Kodaikanal station buses are there because this is hill station and you need to take some taxi.
Yes there are KSRTC buses available and even private buses for local commute and their tickets cost same as KSRTC buses but as you have to go from one place to another like for example from Rajamala to Mathupetty Dam you must preferably rent a car or opt for Uber Rentals so that your travelling can be enjoyable and less tedious.
No in Kodaikanal no buses are available for traveling within the city.. best option is hiring a cab only... if you are a budget traveler u can go by taking lift and by walking