Get a shuttle bus. £6 per head and under an hour journey. Regular departures from different spots in Rome eg Termini, Vatican.
Several different companies, private so not affected by strike and business as usual.
Example of one option...
I've read here that Flixbus (and other shuttle companies) are running a full service on 8th March.
https://www.tripadvisor.co.uk/ShowTopic-g187768-i20-k14683121-o10-Strikes_on_8th_March-Italy.html
With Flixbus you can get to FCO airport from central Rome (Termini, Vatican and other pickup...
Not sure if mentioned elsewhere but the Leonardo express which links Roma Termini to FCO Airport is not affected by the strike, service guaranteed
https://www.trenitalia.com/en/services/leonardo-express.html