The best, safest thing to do is just focus attack backdash the last hit of the kicks. Whats most important in the situations where ibuki is doing the kick attack on you, is to reset spacing. Upball will do damage, and it will likely work once or twice, but if the opponent is quality, they will adapt quickly. Alternatively, the focus attack backdash is relatively safe, does a little bit of damage, and gets her out of your face.
Also, you should ask why is ibuki getting so close to you? Standing stand and low jab and low rh are really really good at keeping her away. The spacing on standing jab is really perfect, it also hits her out of her overhead, and you can throw it out pretty recklessly because there isnt too much she can do to u.
In testing out the standing jab distance, i found that sometimes ibuki will try to slide under it to punish, but if you are close enough, even on hit blanka can still punish the slide., so literally, getting in ibuki’s face and slapping her with jab, getting into kara throw range etc, can really frustrate the ibuki.
If she jumps, use jump fierce in response. I have found that for the most part, ground anti-airs are just not worth it, her jump arc is really large (making it easy to punish with jump fierce), and if you screw up a jump fierce anti air, your not in a lot of trouble, but if you screw up like a low strong anti-air, you are in serious trouble.
Honestly, I love this match. I keep trying to make our local ibuki player better. He is smart, just he really really really hates the blanka match, regardless of the pointers I give him. I am pretty aggressive in the match though.
Finally, when ibuki first came out in super, I did lose quite a bit to her. I never played third strike, and the character was rather foreign. However, once I had a significant number of matches, and played a really long set against just ibuki, I realized that blanka simply zones the shit out of her, can be really aggressive on knockdowns, and must do everything to avoid being knocked down. If you are too passive, ibuki will control the flow of the match, and yer toast. When i say play zoning, I mean staying in the right positions where your moves have better reach and priority than hers, and when that footsying gives you the knockdown or attack opportunity, lay into her with as many jab~elec mixups as you can.