1. visual tempo is sometimes shifting one 8th (not only, sometimes it's a more groovy fourth 16th or third 8th triplet). To be sure i even verified using a DB88 steady metronome. no doubts. i tried changing current source but it's all the same.

2. i can't usb connect to h9 control (i still don't even try midi connections with these problems)

I checked the Tempo LED on a Space we have. It is not perfectly stable as you described. So it is a LED bug (You are the first user who found this issue. Thank you for telling us and I'm sorry about that), but it doesn't affect the sound. It is possible to be fixed during a future firmware update.

For the USB connection problem, there are many reasons could possibly cause the communication error. Normally it's not because of the pedal. I don't think it's your Space's problem, because the last Space you returned also had communication errors. Please try to use another USB cable, or try another PC/Mac. If it still shows communication error, please try to repower your Space and open H9 Control again. If the computer and USB cable are all right, H9 Control should be able to recognize and connect to your Space automatically.