You seem to be correct: there is no limitation of 17 Power Points or 9th-level Astral Constructs on the astral construct power, but the Astral Construct creature entry does not describe what happens when you spend 19 or more Power Points on the power. Numerous forum questions out there exist about this subject (and worse, what happens with Epic shapers).
There was apparently a “Menu D” available at one point, though I’ve seen a few people state it has been “lost,” whatever that means. A search for Astral Construct Menu D found this Mind’s Eye article which has a Menu D, but I think it is for the 3.0 Psionics Handbook, not the 3.5 Expanded Psionics Handbook. Still, might be maybe a bit useful.
Several people also suggest the book Untapped Potential by Dreamscarred Press for its astral juggernaut 9th-level power. It seems reasonable to me to say something like: “Augment: if you spend 19 power points on astral construct, it functions instead as astral juggernaut” if you wanted.