Best places to visit in Trivandrum by bus & luggage storage tips?

Hey all! My friends and I are in Trivandrum for a conference, and we're planning to skip the final day to explore the city. Since we have luggage with us, we’ll be starting our day from Tvm central railway station where we plan to store our bags in the cloakroom. Does anyone have any tips or alternatives for luggage storage. A key detail is that we need to be back at the railway station before 7:45 PM(8:55-train). Any recommendations on places to visit, ideal bus routes, and luggage storage tips would be greatly appreciated. Thanks in advance!