Sure He is, it depends what you mean by it. If you mean by it that He is indwells in creation, or that creation indwell in Him, or that He occupies space and time than... this is incorrect. If you believe He is closer to you than your jugular vein and closer to everything in existence without that closest indicating the closest of my two fingers... or indwelling than yes... Allah is everywhere and sustain everything at every moment. And you will hear the sufis of ahlus sunnah often saying Allah is everything... And this is what they mean... For Allah's closeness is real. And this is correct and does not contradict the Aqida of Ahlus Sunnah (refer to Al Ghazali's creed) And Allah knows best...