Yes. When you edit an activity type, the changes also apply to its future sessions that are already scheduled, except for settings you changed on an individual session. The name and the hide setting always apply to all future sessions.
How to edit an activity type
Go to Play → Activities → Types.
Click the type.
Open the tab you want to change: Details, Prices or Settings.
Click Edit.
Make your changes.
Click Save.
What updates on future sessions
Always: the name and Hide activity type in mobile app and widget.
Unless the session has its own value: minimum and maximum participants, level settings, gender and age limits, registration closes and automatic cancellation.
Price: unless the session has Inherit pricing from activity type turned off.
What doesn't update on scheduled sessions
Categories, organising coaches and tax rate.
Past sessions.
Good to know
A setting you leave the same as the type on a session keeps following the type. A setting you change on the session stays as you set it.
The maximum is never lowered below the number of players already signed up.
Saving the type shows every future session again if you had hidden one session on its own.
If the type has a Company badge, some fields are managed by your company and can't be edited at the club.