Seeking advice: my peach sapling is a freak

I’m accustomed to winging it, with my gardening.
I have the limitation of needing to keep most of my plants in containers; some are in very big containers, but containers, nonetheless.
I live in the vicinity of Olympia Washington.
Here is my current saga:
I was on my way into a local Grocery Outlet and saw 1 last lonely Babcock peach sapling, one of those 3 foot tall leafy twigs in a bag of sawdust.
I bought it on impulse. This was in July.
The one I got last year had died almost immediately, so I wasn’t getting my hopes up.
It was right before a trip, and I ran out of time to plant it before leaving.
It lived.
August came and I was focused on managing my family and working at a Renaissance Faire. I completely forgot about the peach stick.
It lived.
September brought a vertical learning curve with my new work contract...you guessed it...no time.
But now, I watched in morbid curiosity as it happily continued to exist, in its bag.

October is almost over.  We have had frost several times, and are back into intermittent heavy rain.
I finally bored drainage holes in the large  shrub pot I was given to plant it in.
There is gravel and sand in the bottom, to promote drainage.
I have enough neutral soil/compost mix to plant it.
And may have some late season veggies to put around the top to companion with it (and to keep the cat from making it his new toilet.
I have no idea whether it will continue to survive or not.
Any advice on how to proceed would be appreciated.

Seriously, WHAT DO I DO NOW?!

Thank you.

Do you have a greenhouse, or sheltered place? Always nice to provide some aftercare, after abusing a freak..

Hi Freddie, if you have a spot and can plant it in the ground, that would be best. Planting it in a container will restrict root growth, and it will just delay the inevitable need to plant it in the ground, and it's easier to do when they're small. I recommend using the same soil that comes out of the hole to put back in with the new tree. Adding compost, leaves, other soil, guano, fertilizer, etc... encourages the roots to stay in that nice happy spot full of good stuff. By not adding any soil amendments or plant foods, the roots are encouraged to grow outward and down. This makes for good root growth resulting in a stable tree. Hope this helps!

Def get it into the ground. Second the above heavily mulch and add some organic matter to the back fill of soil. Best of luck. This little peach may really, really want to survive.

If you can find a spot with well draining soil, that can help a lot, especially if you get a lot of rain.

Peaches tend to get sickly and disease and pest prone if the soil is too wet.

Hope your tree stays happy and growing well!

Regarding shelter, I can put the pot next to the house, where it will get residual heat. And I am watching for someone getting rid of a Costco carport frame/setup, that I can turn into a greenhouse, but my budget is really low.
I can’t plant anything permanent on the property I’m at, so the grand, gi-hugic pot will have to do.
I have some lovely compost blended with the soil, so, that should help. And I plugged some marigolds that have retreated into their pots in the top bit, around dear little Babby (I have to name it now), since marigolds can be beneficial, and rotting root balls can also, so...either way, Babby wins, right?
Any other companion plant ideas?  There’re a lot of nettles by the patio, near some roses (thought they are going dormant for the season), so that could be a good spot too.
Thank you all. I’ll keep you updated.