Yes, iExplorer can certainly transfer any and all notes on your iPhone to a folder on your Mac or Windows PC. Here’s a tutorial you can follow:
Tutorial: How to export iPhone or iPad notes to your computer
As it explains, iExplorer even includes an Export All option which can transfer all of your notes from your iPhone or iPad to your computer in a single transfer to a folder of your choice.
iExplorer is definitely compatible with an iPhone 4 and iOS 9.1. In fact, it’s compatible with all iPhones, iPads, or iPods ever made by Apple and also works with all iOS versions as long as you are using the most current version of iExplorer 4. Here’s a link to the page to download iExplorer which also explains its other features and benefits: