"scrambled for a hold" vs "scrabbled for a hold"

Both are correct and are synonyms in the usage here considered. Both are traced back to a much more ancient period than that shown by the ngrams, since "scrabble" was acknowledged in the mid 17th century and "scramble" in the late 16th.

(SOED) scrabble [MDu schrabbelen …] 3 v.i. Scramble on hands and feet; stumble or struggle along; Freq. foll. by up. M17.

(SOED) scramble [ imitation: cf. CRAMBLE, SCAMBLE] 1 v.i. Stand up, get into a specified place or position, by the struggling use of the hands and the feet; make one's way by clambering, crawling, etc. over steep or rough ground; move hastily or awkwardly into a specified place or position. L16.

Popularity is very relative criterion but there is a tendency driving people to opt for the popular; I wouldn't say that scramble is more accurate but that it appears to carry more connotations in the way of expressing the idea of a struggling with one's body.