First, this is the development forum ... did you post here as a developer or as someone seeking the most expert advice one could get? ;)
Any whooo ... 1.9 is really old so only some 'old folks' like me might re-call any quirks to 1.9. However, having said that ... a little clarification on your problem ...
What does this mean? "there is no continue button" ... you mean after you have backed up a course or on the first step in the process of backing up a course.
Unless you have some special addon installed in the 1.9, there was no 'autobackup'.
See if there is a backup there already.
Go to the course and in the course menu, click Files link then in the next window, click backupdata.
If there is a backup it's in there. Clicking the backupfilename.zip should prompt you to download it.
And, just in case, a backup from a 1.9 restored to a 2.x/3.x will result in 'no users' brought over *and* the course to which you restore in the 2/3 will be in 'legacy' file mode.
Now if you are a true developer and looking into how to restore a 1.9 backup such that users come in and the files contained in the 1.9 backup come in the new *without* legacy, great! Hope you get it to work.
'spirit of sharing', Ken