On an upgraded instance to Sitecore 9, we are getting the following exception:
Could not resolve type name: Sitecore.Data.SqlServer.SqlServerProxyDataProvider, Sitecore.Kernel (method: Sitecore.Configuration.DefaultFactory.CreateFromTypeName(XmlNode configNode, String parameters, Boolean assert)).
If you decompile Sitecore.Kernel.Dll on your old Sitecore Version and compare it with one on Sitecore 9, you will notice that Sitecore.Data.Proxies namespace has been deprecated now. Additionally ProxyDisabler is no more exists with Sitecore 9.
Conclusion: There are no feasible alternate on Sitecore 9 for Proxies.
Hope this helps.