As Jay J said, check with your building department. Generally for a home you are within the general range. They will NOT be comfortable however. Elderly people will have trouble picking their feet up that high. If this is a home office, you will need additional liability insurance for the home occupation. You are always subject to paying for and being sued for injuries on your property especially in your situation with the public coming in.
Think about building a landing and making a turn so you can shorten the tread height to 6.5" to 7". Another inch or two for tread depth wouldn't hurt either.