Does kitab necessarily mean book in the literal sense?
See 6/38.
Dont know, but yaktubu mean= writen. I guess kitab mean scripture.
walaa junaaha 'alaykum fiimaa 'arradhtum bihi min khithbati alnnisaa-i aw aknantum fii anfusikum 'alima allaahu annakum satadzkuruunahunna walaakin laa tuwaa'iduuhunna sirran illaa an taquuluu qawlan ma'ruufan walaa ta'zimuu 'uqdata alnnikaahi hattaa yablugha alkitaabu ajalahu wai'lamuu anna allaaha ya'lamu maa fii anfusikum faihtsaruuhu wai'lamuu anna allaaha ghafuurun haliimun
Quran also mean = scripture
7518 fa-idzaa qara/naahu faittabi' qur-aanahu
Where there are also another words for something that written, mushaf which is again my opinion, text scroll.