Welcome here, Christopher, glad you managed to gain access now!
That sounds awesome, I sure think Kiva could need some volunteer IT work as there are several parts and features of the website that need improvement; also, I agree that better access for disabled users is more than desirable. I am just not sure how comfortable Kiva's engineers are with having "outsiders" work on their home turf (also because part of the code is probably quite sensitive because of the money and private user information dealt with).
You should in any case contact Kiva's Customer Service (
contactus@kiva.org), though, and ask them to refer you to the competent people. Some of them also browse this site, frequently, so they might contact you anyway.
Best wishes,
Wolfgang.