If cross chaining is your concern, think about the actual change. You'd only get a 6% reduction in gearing with a 50T big ring, which is less than a 1-cog shift. If you're often in the 53/23, then you'd use the 50/21 and still not have quite as low a gear ratio. You'd probably still find yourself in the 50/23 quite often and at the limit of the recommended chain angle.

I have ridden flat terrain with my mountain-geared bike; a 50/34 crank, 11-25 cassette, 11 speed, that has the same 50/23 limit on the big ring. I hardly ever shift to the little ring, except when there's a hill of enough length that I don't want to handle it by staying in the big ring and pedaling standing.

You don't need a 9 speed crank. Any 10 speed model would work.