Sri: All of the schools in Pleasanton are top rated California schools. The slight difference in the schools API will not have a significant impact on the quality of your child's education. Therefore, since all of the schools are impacted due to budget cuts, I would suggest you move to the area in Pleasanton that appeals most to your family and enroll at the local elementary school. Your child will benefit most from going to school with other kids in the neighborhood since there is very little difference in academic quality. All the schools are over 800 API and in an upward trend.
However, when it is time for High School, Pleasanton has open enrollment and the student can choose which High School "fits" better. At that time, it may make a difference to "choose" a school across town for the academic and social fit.
I hope this helps, and let's you relax about where your child starts kindergarten- all the K-5 schools in Pleasanton are just flat out EXCELLENT!
Feel free to contact me if you have any more questions about the area.