Hello Brother,
Banking or Non-banking financial companies can claim only 50% of ITC which is being credited, balance 50% will be getting lapsed. And one of your question was what to do with this 50% (ie, Rs.9,000/-).
You should be carefull even when you make the entries, Since, the 50% of your ITC on input goods or services are inadmissible it should form part of your cost, to be clear, if you are purchasing a A4 bundle for Rs.10,000/- and say it has a GST of Rs.1,800/-. Usually Non-banking companies make necessary entries for Stationery expense as Rs.10,000/- and balance Rs.1,800/- as GST ITC. But here you should Charge the inadmissible ITC to the cost of the product, say, Your stationery expense would be Rs.10,900/- and the GST ITC would be Rs.900/- only.
This is one way, or you can Charge full GST to ITC ledger and then after set off the inadmissible ITC can be charged to Expense ledger through a journal, in this format you could clearly trace the transactions and you can make sure that you had claimed only 50% and balance has been added back to Expense ledger. But this method will be bit complicated and time consuming.
The first step could be more easier as of my opinion.
I hope that this would help you to understand it better, if any doubts then revert back.