What's your idea of messy?

flower petals, more than normal leaves falling-would have to rake up? I have to research a bit more-but seems I read that it has blossoms.

You are going to be hard pressed to find a tree that does not drop spent parts. Even with the small number of fruitless cultivars of trees on the market like fruitless crabapples and fruitless mulberries all the other major components (leaves and flowers) are still generated and shed.

Zone 9 doesn't tell much; in CA, you should get familiar with the state's Generalized Plant Zones, such as is used by Sunset. Ironwoods like coastal conditions best, where they grow with moderate water in well-draining soils. They can be successful grown inland, especially with some coastal influence, but outside of their preferred growing conditions they may show signs of chlorosis. The flowers are nice but turn brown as they age and tend to hang onto the tree in brown clusters. The bark has a nice shedding appearance but adds to the litter produced by leaf fall.

A friend that has one of these in Seattle says there is a more or less continuous rain of dead material falling out of it. So it would probably drive you crazy. Unless the fact that yours is not something like a patio planting perhaps meaning exceptional tidiness isn't actually as much of a requirement. Otherwise a regular stream of litter over long periods is typical of broadleaf evergreens in general. A leaf here, spent flower or fruit parts there coming in a constant dribble. Instead of for instance a big dump of fallen leaves once per year in autumn.