I have an espalier that's about 3 years old, and I've just started another 15 at my allotment, which I'm using as a kind of fence around the edge!
It's relatively easy to do cordons, fans, or espaliers, provided that you have an appropriate space (neither will appreciate deep shade) and you are prepared to watch a few Youtube videos to learn how to prune them and how to identify a fruit bud. Chopping it into the right shape is pretty straightforward. It's the pruning to get it to flower that's a bit more tricky (I am still learning about this).
However, a couple of things about your situation: espalier trees really want to be on a more vigorous rootstock than M9 - M26 or ideally MM106. This sounds counterintuitive, right? An espalier is a small tree, after all! But when you are hitting a tree with such hard pruning, it needs something with a bit of oomph behind it. You could, however, do a cordon with M9.
Also, check your variety because this matters. You do not want to be doing an espalier or cordon tree with a tip-bearing variety, for instance.
You need to make a decision really quite soon, because your tree is actually getting on a bit for this kind of treatment - an unfeathered 1 year maiden is normally used.