You guys do realize that in order for a hacker to grab any credit card details they will need to make a unique custom firmware and make you install it on your PS3 then go on PSN and buy something. Highly unlikely to happen. If you are worried just stick to OFW.
Also most of what these 'hackers' say is BS, e.g. He claims that Sony knows what controllers you're using, what USB devices are plugged in, what sort of television you're using everything.
That fact alone is untrue, a tv cannot send its make or model down scart or HDMI. It's impossible.