Kudos for being aware about the importance of health insurance and starting early. Your age group is the most sought by any insurer as chances of any major hospitalization are minimal and logically premiums are also on much lower side in comparison to higher aged population.
Coming to your query, Considering you being a fit 26 YO, the market rates and your age group, I think the 10L plan premium(I presume you are talking about individual plan) less than 9k makes more sense. For me,you are paying a higher premium in your current 5L plan.
Kindly compare the plans of various insurers both in terms of premium and other features and take an informed call.
Premium seems to be on higher side for SA 5 lakh .
Ideally it should be around 9000 as mentioned by you .
But this premium keep increasing each year with increase in age .
If you pay 20 % more then you get more benefits like
1. Same premium till age 35 .
3. No claim bonus
Recommend to go for 20% extra premium for uniformity and addnl benefits.