Integration with IIB v9

I am running Couchbase Enterprise Server 4.5.1 on a three node cluster. The architectural info is as follows :-
OS - Red Hat Enterprise Edition 7.2
CPU arch - x64

Now I have to integrate this Couchbase server with IBM Integration bus(IIB) v9. For this I am using REST APIs and I am able to perform the retrieval and deletion of data i.e SELECT and DELETE on my couchbaseDB. But when I try to perform the INSERT and UPDATE operation, I am getting the following error :-

“STATEMENT is missing”

I have heard a lot of chatter that maybe REST APIs is not the optimum way to go. Some are saying that I have to use SDK with nodejs or java. Some have even said to update the IIB from v9 to v10.

Could you please help me out as in what should be done to form an integration with IIB v9 ?
Is REST APIs the way to go or should I switch to some other technique ?