I recall some posts here from quite a few years ago where even outdoor Florida growers struggled with the same issues, because even on a patio it needs to be kept to a manageable size. One solution was to use a trellis, and then run the vine around (up and down) as it grows.
You could also get one of those coco fiber covered stakes to do the same thing, the advantage being that it takes up less space horizonally.
If you google Vanilla indoors you'll see some examples of these 2 ways of growing the vine. The examples here (
Vanilla Orchid - STHH Plants show vanilla vines wrapped more or less tightly around the coco fiber stakes.
I don't have personal experience growing vanilla, but these are the ideas I had found when I used to think I wanted one. Assuming you can get it larger enough and give enough sun to be capable of flowering, an important trigger for blooming is that the vine must bend at some point to go downwards again.