The latest versions don't have any PSSnapin anymore.
If you are on PowerShell 4 or higher, and the PowerCLI modules are installed in one of the default locations (AllUsers or CurrentUser scope), you don't need to load anything anymore.
The module auto-load takes care of loading the required module(s) the first time you use a PowerCLI cmdlet.
See also Welcome PowerCLI to the PowerShell Gallery – Install Process Updates
I would advice to go for PowerShell 5.1 and PowerCLI 10.
You will get the latest PowerCLI version automatically when you run the Install-Module -Name VMware.PowerCLI.
You will have to comment out/remove the Add-PSSnapin lines in your scripts I'm afraid.
Blog: lucd.info Twitter: @LucD22 Co-author PowerCLI Reference