I am facing a similar problem as the one mentioned in the below link:

Performance Degradation going from DB2 v8.2 to DB2 v9.1

Can somebody plz help me in finding a solution in this regard?

I'd suggest to start by reviewing the following article:
Tips for improving INSERT performance in DB2 Universal Database

It's a bit old but most of the info is still relevant. It has some general info on how to improve insert performance.

If the table has indexes (especially a clustering index), then performing index reorg with the cleanup option prior to running inserts *might* help.

If the problem only happened after v8-v9 upgrade, then testing with the latest (or more current) fixpak is not a bad idea.