In Ireland, organised activities (sports, developmental groups such as Scouts/Guides etc) are allowed to continue for children of schoolgoing age even though we are in tier 5 - they are in the same categorisation as schools. We need to maintain social distancing, non-contact activities, pods no larger than 15 outdoors or 6 indoors, preferably all activity outdoors, maintain a register of attendance, sanitise hands and equipment, sanitisation gap between groups so 1 group leaves before the others start to arrive and no cross-over...…..it's a long list of requirements on the organisers of such activity, but it does mean that DCs of schoolgoing age have something to do outside of school (keep going to their normal activities - not that you can suddenly join in) in lots of cases - but some are not possible like swimming. I don't know about things like dance, speech and drama, music, etc if outside the school setting.
In our Cub pack, we are running each activity twice, with 2 out of our 4 patrols in each session (6 Cubs in each patrol). While some Cubs are in the same schools, there are a number of different schools within the pack, some have 3/4 schoolmates while some are on their own. So trying to do a school-based bubble would not work. But we are being strict on the Patrols as the Cubs bubble.
But while it is very strict, and a LOT more work for the 3 volunteer Leaders, we have between 85%-100% turnout on a weekly basis since we started back in September, including once we had been subject to lockdown.
I know gaelic football, hockey, soccer and solo-sailing have all managed to keep going this way too locally.