Live Results are automatically enabled for all leagues except Cricket leagues.
You can disable Live Results in:
Setup > Settings > General Site Settings (tab)
Then uncheck the check box labelled: Enable Live Results And Team Admin App
Any matches that have a 'Latest score' entered instead of a 'Final Score' will have the scores deleted when you disable Live Results.
Disabling Live Results will also prevent users in your league from entering scores via the Team Admin app.