Karthikeyan was the sole leader with 7.5 points, while Kumaran, top seed IM Diptayan Ghosh, Sidhant Mohapatra, Arvindh Chithambaram and Harsha Bharathakoti remained joint second half a point adrift.
There was a major upset in the girls section as unfancied Riya Savant (6.5) of Goa stunned top seed and overnight leader WFM M Mahalakshmi (7), enabling V Varshini snatch the sole lead with 7.5 points.
Having outwitted second seed G K Monnisha earlier, Varshini kept her winning run as she defeated Shiny Das to take the lead.
Results (Round 9)
Boys: B Kumaran (7) drew IM Murali Karthikeyan (7.5); IM Diptayan Ghosh (7) drew Sidhant Mohapatra (7); Mohammad Nubairshah Sheikh (6) lost to FM Aravindh Chithambaram (7); Nr Vignesh (6) lost to Pranav Vijay (7); Al Muthaiah (6) lost to Harsha Bharathakoti (7); K Anshuman (6) lost to N Krishna Teja (6.5); Nr Visakh (6.5) b Abhishek A (5.5); Karthik (5.5) lost to Ajay Krishna S (6.5); Ritviz Parab (6.5) b Audi Ameya (5.5); Rajdeep Sarkar (6) drew Rohan Ahuja (6); Naik Rishubh Naresh (6.5) b M Satvik (5.5); Koustav Chatterjee (5.5) lost to FM Rakesh Kumar Jena (6.5); Nishant Kumar (6) b V Pranavananda (5); A Visveshwar (5) lost to Aradhya Garg (6); FM Mitrabha Guha (6) b Raghav Srivathsav V (5).