The only obvious solution I can think of right now would be to add a small SAS 9.4, single server installation to your hosted solution. That will work fine with any version of EG. From what I understand, quite a lot of SAS customers are choosing a hybrid upgrade strategy which means maintaining both SAS 9.4 AND SAS Viya most likely for reasons like the one you have.
I suggest you ask your SAS account manager to arrange a session with a SAS architect you can walk you through available options. They are the ones most familiar with these types of migration issues and what solutions are possible.