You can install the instantclient downloading the files from Oracle.
You may have noticed that using the the installation instructions, you unzip the library on a directory but when you try to load them you will end with a Developer cannot be verified or something other similar message fron osx.
The problem is that the code is not signed by Oracle and osx marks it with a com.apple.quarantine. You can see the at sign at the end of the file anmes doing a
> ls -l
-r-xr-xr-x@ 1 staff 5780 Feb 22 2019 BASIC_LICENSE
com.apple.quarantine 57
-rw-r--r--@ 1 staff 1670 Aug 19 05:57 BASIC_README
The solution is to give exucution permissions to all files and then remove the extra @ attribute.
cd instantclient_19_3
chmod u+x *
cd ..
xattr -r -d -s com.apple.quarantine instantclient_19_3
Now you can load and use the library form your programs.
Taken from Gary Gordhamer.