Is purl a word in the Scrabble Dictionary

Yes, purl is playable

...and is worth 9 points.

Found in the following dictionaries

Enable (Words with friends)
SOWPODS (Collins Scrabble Words)
OTCWL2014 (NASPA Word List 2014)
TWL06 (NASPA List 2006)

"Purl" Definition

noun

A decorative edging of lace or embroidery.
Gold or silver wire used in embroidery.
Inversion of a knit stitch; purl stitch.
The sound made by rippling water.
Gold or silver thread or wire for embroidering or edging.

verb-intransitive

To do knitting with a purl stitch.
To edge or finish with lace or embroidery.
To flow or ripple with a murmuring sound.

verb-transitive

To edge or finish (a handkerchief, for example) with lace or embroidery.
To knit (yarn) with a purl stitch.

verb

To embroider with gold or silver thread.
To edge or border with gold or silver embroidery.
To knit in purl stitch.
To do knitting in purl stitch.
To make a soft murmuring sound like that of a stream.