How to pronounce "slash" in giving an address

I agree, in the US / is called "slash".
But perhaps something else is common in the UK.
I find this:

stroke
NOUN
2.2 A short printed or written diagonal line typically separating characters or figures

Oxford Dictionaries

..

I think I saw this in the Terry Gilliam movie Brazil. In the big office building, the number on a door has a / character, but they pronounce it "stroke".

This may well be one of those common things showing significant regional variation.

In my part of the world (Melbourne, Australia), this address wouldn't refer to "the corner of 2 streets" as suggested in the question. It would mean "internal address 1" (e.g. a unit, an apartment, or in general the ordinal dwelling/office of several such on that site) at "street address 9 Park Lane".

As such, it would more often be read aloud as "one of nine Park Lane" or, to disambiguate, "unit one of nine Park Lane" (even if it's an apartment rather than a "unit"), although pronouncing the "/" as "slash" is also common.

Given it's spoken, I'm finding it hard to locate any online evidence to support this, so you'll just have to take my word for it.

In the US, / is pronounced slash. However, I would not have the foggiest idea what 1/9 Park Lane meant as an address. I might take a guess that it meant 9 Park Lane but the 1 would be a mystery. Likely, when you said that, I would say

Huh?

It certainly does not convey that you are at the corner of Park Lane and some other street, much less which of the four corners you are at.

The way we would say it here is:

I live at 9 Park Lane. That is at the corner of Park Lane and Parkland Avenue. The building is (some identifying characteristic of the building) and I'm in Apartment 6C.

As for what you would write down, if asked for your address in writing:

Apartment 6c

9 Park Lane

Park City

State, Zip Code

The mailman does not need to be told that you are on a corner, or if he does, you are in deep kimchi.

As for references, as @Chappo said, you'll just have to take my word for it. :)