The executive order opens an option for deferring Social Security payroll taxes for some people. It does not eliminate the tax; it allows a deferral of the collection of certain Social Security tax payments from September 1 through Dec 31, 2020. At this time (8/19/2020), it appears the unpaid Social Security tax would have to be repaid, unless a new law forgives the liability.
Please consult with your tax advisor to decide if you want to defer the payment of the relevant portion.
See: Deferring Payroll Tax Obligations (official memorandum)