It's perfectly supported. Are you going to do it to coincide with an app release upgrade or just doing the migration?
It's really pretty straight forward to do, the size of your overall environment and database will determine how complex it has to be. I've done this migration numerous times and typically will use some form of ETL tool to handle the largest tables and then just setup data sources and run R98403 to handle the rest of them. In your case though, it obviously would entail setting up new enterprise servers as well and maybe web servers depending on where you have websphere running. So, in short - it's no small undertaking and to me it would make more sense to do it at the same time as an app upgrade to 9.2.