Hi, I just finished the wiring diagrams in Eeschema. I have a huge doubt on the ground plane and the power plane. My main question is about the power plans, as I will use a font of 9 volts and circuit design has power pins of 9 volts and 7.5 volts. What do I do now?
I don’t know if I really get your question.
So you have a single source (9 volts) but need another voltage level (7.5 volts) to supply certain components?
Check the min/max ratings in the datasheet of your 7.5 volt device. Maybe it is capable to be supplied with 9 volts. If not you will need to create the 7.5 volts out of your 9 volts.
http://www.freeinfosociety.com/electronics/schemview.php?id=2291
Check the link, it contains the circuit diagram I’m working on. Note the 9V and 7.5V pins distributed by the circuit. This project works only with a source of nine-volt negative center.
By the way, thanks for contribute! 
Curious. I’m working on a design to be compatible with a Roland product (parent company of Boss) and it uses +9V, +7V, -7V and 5V. Looks like they like to keep everyone on their toes.
It seems to me that the 7V5 components don’t have any 9V connections, so you’d be able to create a power plane to locate those in specifically if you thought that was the best way. Is there a reason you’d prefer not to have a 9V power plane and route these specific connections as tracks?
While not in the schematic in your link, a low dropout adjustable linear voltage regulator will do the trick of giving you a 7V5 line if that’s what you’re asking. Something like the LM1117.
Geoff