ENH: pd.date_range for 9am each day between two pd.Timestamp objects
#### Is your feature request related to a problem?

What I have:

```
pd.Timestamp('2021-07-05 08:10:11')
pd.Timestamp('2021-07-07 12:13:14')
```

What I'm looking for:

```
[pd.Timestamp('2021-07-05 09:00:00'), 
 pd.Timestamp('2021-07-06 09:00:00'), 
 pd.Timestamp('2021-07-07 09:00:00')]
```


#### Describe the solution you'd like

It feels like I should be able to do this with some combination of of `pd.date_range` and `pd.offsets`, but I can't find the right combination. 

Given that 9am is the standard meteorological time point, I'm hoping someone has a nice solution for this already!

If it's possible and graceful, this is just a documentation issue I'm happy to put a PR in for...

#### alternatives / additional context

This is way more fiddly that I expected, I've started a gist to collect current possible implementations along with test cases to verify they work:

https://gist.github.com/cjw296/73af04f7a4dcbc39f2ec01384bf5aa90

I've also thrown a question up on StackOverflow in case I'm just missing something obvious:

https://stackoverflow.com/questions/68267555/pd-date-range-for-9am-each-day-between-two-ps-timestamp-objects
