All of the Spanish Episodes are in Dailymotion
YouTube used to have all of the spanish dub before AuxiliaryMode took action and delisted almost the whole show, but it turns out the entire spanish dub is in Dailymotion, which is still up for 9 years, I managed to look up some Spanish blog to find the entire dub (minus Fire Starter but that episode is found already).
https://teorias-karra.blogspot.com/2014/12/kevin-spencer-temporada-1-completa.html https://teorias-karra.blogspot.com/2014/12/kevin-spencer-temporada-2-completa.html https://teorias-karra.blogspot.com/2014/12/kevin-spencer-temporada-3-completa.html https://teorias-karra.blogspot.com/2014/12/kevin-spencer-temporada-4-completa.html https://teorias-karra.blogspot.com/2015/01/kevin-spencer-temporada-5-completa.html https://teorias-karra.blogspot.com/2015/01/kevin-spencer-temporada-6-completa.html https://teorias-karra.blogspot.com/2015/01/kevin-spencer-temporada-7-completa.html https://teorias-karra.blogspot.com/2015/01/kevin-spencer-temporada-8-completa.html
There's also a Catalan dub that aired the first 4 seasons, most of them are partially found (most episodes are blocked by Auxiliary, but can be accessed by a Spain VPN) https://kevinspencercatala.forocatalan.com