Both v9 and v8 accept old and new api.

xml coding also is same.Even the documentation is similar

what you need to check is that :

-in python they may have changed the field or function name.You will have to find and change it accordingly.

-the same applies to xml also, check field and record's id names are same or not

V9 and V8 accept old and new api.

Above answer is we have to check. And one more thing is than import statements. We should check import statement also.