The NRSV-CE (1989) comes from the RSV-CE (1966), which is a 1946 Protestant translation with all canonical books included (pp. xviii & 9 of Which Bible Should You Read?).
The NRSV-CE omits "fasting" in its translation of Mk. 9:29 (so does the NABRE):
He said to them, “This kind can only come out through prayer.”
cf. Rheims's Mk. 9:28:
And he said to them: This kind can go out by nothing, but by prayer and fasting.
Fasting scandalizes "modern man," so it's left out.
Which Bible Should You Read? pp. 28-30 gives another example of a glaring omission of verses in nominally Catholic bibles: Ecclesiasticus (Sirach) 24:24-31. The Douay version reads:
... [24] I am the mother of fair love, and of fear, and of knowledge, and of holy hope.
Ego mater pulchrae dilectionis, et timoris, et agnitionis, et sanctae spei.
... [25] In me is all grace of the way and of the truth, in me is all hope of life and of virtue.
In me gratia omnis viae et veritatis : in me omnis spes vitae et virtutis.
... [26] Come over to me, all ye that desire me, and be filled with my fruits.
Transite ad me, omnes qui concupiscitis me, et a generationibus meis implemini :
... [27] For my spirit is sweet above honey, and my inheritance above honey and the honeycomb.
spiritus enim meus super mel dulcis, et haereditas mea super mel et favum.
... [28] My memory is unto everlasting generations.
Memoria mea in generatione saeculorum.
... [29] They that eat me, shall yet hunger: and they that drink me, shall yet thirst.
Qui edunt me, adhuc esurient, et qui bibunt me, adhuc sitient.
... [30] He that hearkeneth to me, shall not be confounded: and they that work by me, shall not sin.
Qui audit me non confundetur, et qui operantur in me non peccabunt :
... [31] They that explain me shall have life everlasting.
qui elucidant me, vitam aeternam habebunt.
But the NRSV-CE of Sirach 24 omits the bold verses above, and NRSV-CE v. 19 corresponds to Douay v. 26! Douay vv. 24-25's omission is explained in a footnote of the NSRV-CE, but the NRSV-CE doesn't explain its omission of Douay v. 31 in a footnote!
These verses were probably omitted because the Catholic Church uses them in the liturgy for various feasts of the Blessed Virgin Mother, and mention of her is a scandal to Protestants.
According to Which Bible Should You Read? p. 29,
All together, Chapter 24 of Ecclesiasticus (Sirach) has some […] 13 fewer verses in the CRSV [Catholic Revised Standard Version] than the Vulgate and DRB [Douay-Rheims Bible]!
Indeed, the Douay version has 47 verses, and the NRSV-CE has only 34.
The "old Latin vulgate" is the only official edition of Holy Scriptures for the universal Church, as defined in the Council of Trent.