The Varsity Scouts program has not yet been been implemented in Scoutbook. I believe the development team is aware that the varsity advanvcement program is the Trail to Eagle Scout plus additional "letters" and awards.
Venturing on Scoutbook is in beta test. 2015-09-29: For a discussion of where the Venturing Subscription BETA is see Venturing Program thread
From the BSA point of view, at a certain age (about 14-17) a boy can be registered as a member of all senior scouting unit types at one time. Certain special Scouts do not have a top age limit.
I believe BSA also does not require a Venturer or Sea Scout (who is eligible to work on the trail to Eagle Scout) to be registered in a troop or team.
Requiring a Sea Scout to be dual registered in a team or crew has been discussed by BSA (not Scoutbook) as a possible option for Sea Scouts. Some of these issues have been posted and discussed in the Varsity Scout, Venturing, Sea Scout and other Scoutbook forums.
New program enhancements are temporarily frozen while Scoutbook is changed to a cloud based system and some performance enhancements are done. For status of performance enhancements see the Director of Scoutbook updates in the Scoutbook blog
updated 3 years ago