I just noticed that they only have half the hit dice of an iron golem, yet are the same size and have similar characteristics.
Yes that is a puzzler. It also does a lot less damage than a 2E Iron Golem - 4d4 instead of 4d10.
Maybe it's a "poor man's Iron Golem". A hollow framework of blades welded together, instead of a solid construction like the SRD Iron Golem.
So, apart from the 9 Hit Dice are there are other changes you fancy.
Modify the stats a bit? With only 9 HD, 45 hp and 4-16 damage it is more like a Flesh Golem in power.
How about putting it between a Flesh and a Stone Golem in strength.
Spiked Golem: HD 9d10+30 (79hp), Str 25, Dex 9, Con 0, Int 0, Wis 11, Cha 1, NA +18 ?
Attacks ought to be 2 blades or spikes, but how much damage should they be do?
A Large armour spike only does 1d8 damage. The original 4-16 damage is marginally more than a Flesh Golem's 2-16, so I'd be OK leaving it at 2d8 damage with a higher Strength bonus for blade/spike +12 melee (2d8+7).