Is there a good T9 texting app?

Question

After using a regular phone for so long, i've gotten used to using the t9 word to text. Is there a good app that uses T9?

Answer 1

No. T9 is applicable only to phones that use numeric dial pads instead of true qwerty keyboards. You can't text using the phone dial pad on an iPhone - only the keyboard.
Although you're used to the T9 and numeric dial pad, with a little practice the keyboard is as fast or faster, particularly when you use real English words instead of texting "abbreviations."
Change is good.
I'd hardly call the QWERTY keyboard, well over a century old, "Change". It is designed to be used with two hands with all fingers, not on a device that is barlely over half my single handspan with each "key" a tenth of my thumbprint. The numeric keypad plus T9 was truly innovative allowing very fast imput using one hand/digit on devices that were very small. It makes a lot of sense. This is a massive technological step backwards.
And abbreviations don't fit in with T9, 'txt' language came before with the slower method of scrolling through charecters by button hits - people just continued using it in the T9 era because they liked the abbreviations.