Gen
macrumors 6502a
And since the OP said he'll be using those applications, this is all completely relevant! 🙄 For the OP's uses, the better graphics card will make no difference. The only place he might make use of it is in Keynote, but $300 to make Keynote animations render a tiny bit quicker seems like poor financial planning to me.
The 9400M is a very capable chip, and more than sufficient for 99% of what most users will be doing. Your money is better spent on RAM and storage upgrades.
Maybe I'm old fashioned, but why purchase a MBP if you're not going for the discrete graphics? If the OP wants to save money and only get the weaker 9400 then he should opt for the 13" variant.