Great icons, good price [at Nov 30th, 2011; 5:11 AM]
8 / 10
The Rainbow Scroll had been the cheapest 9-iconer until the 2011 Game Master Challenge. Suddenly the bargain offered by the scroll (which displaced classics such as Ice Club) suddenly finds itself three times the price of the now plentiful Ridiculously Heavy Battle Hammer.
Nonetheless, though its price to power ratio is no longer quite the deal it was, the scroll's icons are superior to those of the battle hammer in most situations, such as against the ability burrow and common shields such as Shiny Shoal Shell Shield and Leaf Shield. In fact, the Rainbow Scroll offers some of the best types among 9-iconers until you can afford a Golden Compass.
In summary, if you only play against one player opponents, you'll do fine with two battle hammers. However, if you want to win a battle with a friend, you may find the strategic value of this to be worth the extra cost.
Cheapest 9-iconer [at Jul 25th, 2010; 8:12 AM]
9 / 10
The cheapest 9-iconer to date, which uses both air and light, which are both quite rare icons, I'd nearly even say the "best" 9-iconer. (Not counting one that has additional effects)
Also potential choices for 1-player battling are the cheap Voidberry Potion and the more expensive Prickly Potion, which use reflecting icons, meaning that in 1-P, unless you opponent is frozen, you will use his/her/it's STR boost.
Those that can't afford this weapon (Which is only 10 days of playing Kass Basher) may want to look at 17-Pound Trout or even the Scarab Ring.