BUG: pytables in py39
There are failures I'm getting locally since homebrew bumped up to py39.  I'm not seeing them on the CI, but they _did_ appear around the same time as these [different](https://dev.azure.com/pandas-dev/pandas/_build/results?buildId=48423&view=logs&j=2d7fb38a-2053-50f3-a67c-09f6e91d3121&t=449937cc-3d50-56b5-5662-e489f41f1268) unexplained pytables failures started showing up.
can you add pytables to the 3.9 build (I guess its built now?) https://github.com/pandas-dev/pandas/blob/master/ci/deps/azure-39.yaml > can you add pytables to the 3.9 build (I guess its built now?) https://github.com/pandas-dev/pandas/blob/master/ci/deps/azure-39.yaml

it doesnt have a wheel, so i think the build would take too long it needs to be installed via conda forge

i am sure it's there > it needs to be installed via conda forge

sounds good, just pushed i think that worked, great. There is an issue to add more deps to this build let me bump it. I guess should put a release note? > I guess should put a release note?

for 1.1.x? > > I guess should put a release note?
> 
> for 1.1.x?

hmm yeah

while you are at it, can you add scipy and pyarrow==1.0 (though not sure they support 3.9 with that version) scipy/pyarrow added and green Owee, I'm MrMeeseeks, Look at me.

There seem to be a conflict, please backport manually. Here are approximate instructions:

1. Checkout backport branch and update it.

```
$ git checkout 1.1.x
$ git pull
```

2. Cherry pick the first parent branch of the this PR on top of the older branch:
```
$ git cherry-pick -m1 336cc6cba3188beb731b79ad55b1d86ddd0e25f0
```

3. You will likely have some merge/cherry-pick conflict here, fix them and commit:

```
$ git commit -am 'Backport PR #38041: BUG: pytables in py39'
```

4. Push to a named branch :

```
git push YOURFORK 1.1.x:auto-backport-of-pr-38041-on-1.1.x
```

5. Create a PR against branch 1.1.x, I would have named this PR:

> "Backport PR #38041 on branch 1.1.x"

And apply the correct labels and milestones.

Congratulation you did some good work ! Hopefully your backport PR will be tested by the continuous integration and merged soon!

If these instruction are inaccurate, feel free to [suggest an improvement](https://github.com/MeeseeksBox/MeeseeksDev).
                