Document Categorization Problem
Except for the OCR part, the right bundle would be pandas and sklearn.

You can check this ipython notebook which uses TfidfVectorizer and SVC Classifier.

This classifier can make one-vs-one or one-vs-the-rest multiclass predictions, and if you use the predict_proba method instead of predict, you would have the confidence level of each category.

If you're looking for performances and you don't need prediction confidence levels, you should use LinearSVC which is way faster.

Sklearn is very well documented and you will find everything you need for text classification.