Yes, you can have as many Novo accounts as you have businesses. Right now, you will need multiple logins for your separate businesses, but this is something that we hope to support in the future.
Currently, we are unable to support opening up multiple accounts per business, also known as sub-accounts. However, our users are able to add notes and tags to each of their transactions so that you can export this information as a CSV file of your transaction. This way, you will be able to easily filter through your transactions or integrate with your account tools (such as QuickBooks).
Please see this FAQ for the features that are included with our accounts.