You should take a look at the document Best Known Methods for Installing LANDESK Management Suite 9.6 (with videos)
Also, LANDESK Management Suite 9.6 Architecture - Overview may help as well
My recommendation is you start fresh and not do an in-place upgrade. A side-by-side upgrade, to 9.6 SP2, is what I would do. This also gives you the opportunity to step up to Server 2012 and that should hold you off for some time.
I am also looking at upgrading to version 9.6 SP2 from 9.5 SP2. Do you have to install SP1 for 9.6 before installing SP2 or can you just jump to SP2?
Nope, you just need to install 9.6 first and then SP2. No need to do SP1.
Thank you for the documents.
Databases i can using backup and restore method, is it right?
And how about the existing client when the management console has upgraded to 9.6 SP2? still managed or i should redeploy package or just upgrade?
You can use a backup and restore method if you'd like but it may be best to start with a fresh DB. This saves from carrying over any corrupted data or DB issues which may exist on your current DB. You can always copy items from one core to the other using Core Sync, "Copy to other core", or export\import. This all depends on preference and how many items you have on the old core.
As for the clients, there are a number of ways to handle it. What I have done in the past is to use a DNS alias for the core server. This will make the clients think they are talking to the old core but, in reality, they are being redirected to the new core. Once they are on the new core, you can re-deploy the clients. Key here is to make sure you have copied the certs from the old core over to the new core.
Another option is to use the old core to push out the agent from the new core. You will have to create a self-contained client and deploy it as a distribution package from the old core.
In either situations, I would encourage that you setup a DNS alias and use that in your agent configs going forward. This will make upgrading and disaster recovery much easier from a client perspective.
Hope all this makes sense