Just to clarify, there are two elements to consider here: the BigBlueButtonBN Plugin in Moodle and the BigBlueButton server by itself.
The meeting activity/room needs to have the option "Session can be recorded" enabled in order to have the recording function available in BigBlueButton. That can be enabled by default by configuring the plugin
Site administration->Plugins->Activity modules->BigBlueButtonBN
Section, Configuration for "recording" feature -> Recording feature enabled [checked], which it is by default.
If you don't want Teachers to change that in the room/activity, uncheck the "Recording feature can be edited". That will affect only the new activities/rooms created.
Now, for what I understand what you want/need is BigBlueButton to start recording since the first user joins the session, as it was in version 0.81. Well, the start/stop button added on 0.9 was a long time waiting feature for us to put in place and there were a big number of users who were asking for it since version 0.71 came out, so this is why you see it there
This is in the BBB configuration and it can not be changed in any way from an external application (the Moodle plugin in this case).
If you own the BBB server, what you could do is to set it up in a way that the old behavior is applied to all the sessions in that server.
You would need to edit
And change the values that come by default:
But again, that will apply to all the sessions in that server. The downside on that is that you may have (as before) a long gap at the beginning of the session before the class even start, and at the end until the last user left or the meeting is ended.
I hope this helps,