Does IControl has an API to return connection count of members in LTM module ? If yes, please share it. Thx.

You can retrieve the pool member stats, including the current connection count, for all members of a pool by hitting the member stats page:

I.e.: https://MyF5.com/mgmt/tm/ltm/pool/pool_10.3.3.31/members/stats

You can also retrieve stats for individual pool members by hitting the individual member's stat page:

I.e. https://MyF5.com/mgmt/tm/ltm/pool/pool_10.3.3.31/members/~Common~10.3.3.31:80/stats

I believe the value you will want to examine is serverside.curConns to get the current connection count.